Encapsulation of herbicides to reduce crop injury

ABSTRACT

Methods of reducing injury to crop foliage and achieving weed control using encapsulated acetamide herbicides are described. Herbicidal microcapsules comprising herbicide core material and a shell wall encapsulating the core material are also described. The microcapsules provide reduced crop injury through controlled herbicide release.

This application is a continuation of U.S. patent application Ser. No.15/860,733, filed Jan. 3, 2018, which is a continuation of U.S. patentapplication Ser. No. 12/705,789, filed Feb. 15, 2010, issued as U.S.Pat. No. 9,877,478, and claims the benefit of U.S. Provisional PatentApplication Ser. No. 61/152,533, filed Feb. 13, 2009, the entiredisclosures of which is incorporated herein by reference.

FIELD OF THE INVENTION

The present invention generally relates to methods of reducing injury tocrop foliage and achieving commercial weed control using encapsulatedacetamide (e.g., acetanilide) herbicides.

BACKGROUND OF THE INVENTION

The emergence of glyphosate-resistant weeds has generated interest inthe use of residual herbicides as tank-mix partners with glyphosate inglyphosate-tolerant (e.g., ROUNDUP READY or RR) crops. Acetamideherbicides, including, for example, acetanilide herbicides, typically donot offer significant post-emergence activity, but as a residual partnerwould provide control of newly emerging monocots and small-seeded dicotweed species. This would usefully supplement the activity of glyphosatewhich is effective on emerged weeds, but lacks significant residualactivity.

Acetanilide herbicides have traditionally been applied to the soilbefore planting as pre-emergent herbicides. The application ofacetanilide herbicides prior to emergence of the crop, however, hascaused many crops to be damaged or killed. In response to this problem,it was proposed to apply commercially available acetanilide herbicideformulations after the emergence of the crop (i.e., post-emergent to thecrop), but before the emergence of later germinating weeds (i.e.,pre-emergent to the weeds). Application during this time window,however, caused unexpected foliar injury to the crop. The injury wasobserved with both commercially available conventional acetanilideemulsifiable concentrate (EC) formulations and with commerciallyavailable encapsulated acetanilide formulations.

Prior art microencapsulation procedures are generally adequate forproducing formulations with good weed control. However, the practitionerof this art has had some difficulty optimizing the release rates toobtain acceptable bioefficacy for a given active while minimizing cropinjury to commercially acceptable levels. In particular, commercialencapsulated formulations may show greater systemic crop plant injuryover time in the form of leaf crinkling and plant stunting when comparedto emulsifiable concentrates.

In microencapsulation technology known in the art, core herbicide istypically released from a microcapsule at least in part by moleculardiffusion through the shell wall. Modification of shell wall thicknessto increase or decrease herbicide rate has definite limitations.

Thin shell walls are sensitive to premature mechanical rupture duringhandling or in the field, resulting in immediate release. Poor packagestability resulting from shell wall defects can also arise when the corematerial is in direct contact with the external vehicle. As a result,some core material may crystallize outside the capsule causing problemsin spray applications, such as spray nozzle plugging. Further, highershear encountered in certain application means, such as sprayapplications, can result in shell wall rupture and herbicide release.The microcapsule thus becomes little more than an emulsion stabilizedagainst coalescence. When delivered to the field, herbicide release isso fast that little crop safety improvement is gained over conventionalemulsion concentrate formulations.

If the wall thickness is increased, the bioefficacy quickly drops to amarginal performance level because herbicide release is delayed. Thereis also a practical limit to the wall thickness in interfacialpolymerization. As the polymer precipitates, the reaction becomesdiffusion controlled. The reaction rate can drop to such an extent thatnon-constructive side reactions can predominate.

Various formulation solutions have been attempted to address the releaserate limitations. For example, two package or single package blends ofmicrocapsules and dispersions or emulsions of free agricultural activeshave been proposed in Scher, U.S. Pat. Nos. 5,223,477 and 5,049,182.Seitz et al., U.S. Pat. No. 5,925,595 and U.S. Publication No.2004/0137031 A1, teach methods for producing microencapsulatedacetochlor. The degree of permeability is regulated by a compositionalchange in the precursors for the wall. Although the Sietz compositionshave proven effective for weed control, unacceptable crop injury hasbeen observed in connection with the use of those compositions whenapplied to certain commercially important crops.

A need therefore exists for herbicide compositions and methods utilizingacetamide herbicides such as acetamide herbicides whereby simultaneouscommercially acceptable weed control and commercially acceptable cropinjury can be attained.

SUMMARY OF THE INVENTION

Among the various aspects of the present invention may be noted theprovision of encapsulated acetamide herbicide compositions and methodsfor use thereof. The present invention provides for post-emergence cropand pre-emergence weed application of the encapsulated acetamideherbicides wherein herbicide release rate is controlled in order to giveboth commercially acceptable weed control and commercially acceptablecrop injury.

Briefly, therefore, one embodiment of the present invention is directedto a particulate microencapsulated acetamide herbicide comprising awater-immiscible core material comprising the acetamide herbicide and amicrocapsule having a shell wall comprising a polyurea, the microcapsulecontaining the core material. The shell wall is formed in apolymerization medium by a polymerization reaction between apolyisocyanate component comprising a polyisocyanate or mixture ofpolyisocyanates and a polyamine component comprising a polyamine ormixture of polyamines to form the polyurea. The ratio of amine molarequivalents contained in the polyamine component to isocyanate molarequivalents contained in the polyisocyanate component is at least 1.1:1and a population of the microcapsules has a mean particle size of atleast about 7 μm.

Another embodiment of the present invention is directed to a particulatemicroencapsulated acetamide herbicide comprising a water-immiscible corematerial comprising the acetamide herbicide and a microcapsule having ashell wall comprising a polyurea, the microcapsule containing the corematerial. The shell wall is formed in a polymerization medium by apolymerization reaction between a polyisocyanate component comprising apolyisocyanate or mixture of polyisocyanates and a polyamine componentconsisting essentially of a principal polyamine to form the polyurea. Apopulation of the microcapsules has a mean particle size of at leastabout 7 μm.

Another embodiment of the present invention is directed to a particulatemicroencapsulated acetamide herbicide comprising a water-immiscible corematerial comprising the acetamide herbicide and a microcapsule having ashell wall comprising a polyurea, the microcapsule containing the corematerial. The shell wall is formed in a polymerization medium by apolymerization reaction between a polyisocyanate component comprising apolyisocyanate or mixture of polyisocyanates and a polyamine componentcomprising a polyamine or mixture of polyamines to form the polyurea. Apopulation of the microcapsules has a mean particle size of at leastabout 7 μm and the shell wall is of limited permeability. The nature andcomposition of said shell wall and encapsulated acetamide is such that,when an aqueous slurry consisting of 1% by weight of the encapsulatedacetamide herbicide in an aqueous medium consisting of deionized wateris subjected to agitation at a rate sufficient to maintain the particlesin suspension without mechanical rupturing, the acetamide content of theaqueous medium remains less than 100 ppm after agitation for 6 hours at25° C., and less than 150 ppm acetamide after agitation for 24 hours at25° C.

Yet another embodiment of the present invention is directed to a methodof controlling weeds in a field of crop plants, the method comprisingforming an application mixture comprising the particulatemicroencapsulated acetamide herbicides of the present invention andapplying the application mixture in a herbicidally effective amountpost-emergent to the crop plants.

Another embodiment of the present invention is directed to a method ofcontrolling commercially important weeds located in a field of cropplants. The method comprises forming an application mixture comprising aparticulate encapsulated acetamide herbicide composition and applyingthe application mixture in an herbicidally effective amountpost-emergent to the crop plants and pre-emergent to the weeds. Theparticulate acetamide herbicide comprises shell/core particles eachhaving a core comprising acetamide contained within a shell of limitedpermeability, and the nature and composition of said particulateencapsulated acetamide is such that, when an aqueous slurry consistingof 1% by weight of the encapsulated acetamide herbicide in an aqueousmedium consisting of deionized water is subjected to agitation at a ratesufficient to maintain the particles in suspension without mechanicalrupturing, the acetamide content of the aqueous medium remains less than100 ppm after agitation for 6 hours at 25° C., and less than 150 ppmacetamide after agitation for 24 hours at 25° C.

Another embodiment of the present invention is directed to a method ofcontrolling commercially important weeds located in a field of cropplants. The method comprises forming an application mixture comprising aparticulate encapsulated acetamide herbicide composition and applyingthe application mixture in a herbicidally effective amount post-emergentto the crop plants and pre-emergent to the weeds. The rate of cropinjury is no more than 20% for the time period of from 1 day to 28 daysafter applying the application mixture to crop plants in the growthstage range of from crop emergence to the six-leaf growth stage and therate of weed control is at least 60% for the time period of fromapplication of the application mixture to 12 weeks after application ofthe application mixture.

Other objects and features will be in part apparent and in part pointedout hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a graph depicting cotton injury that occurred withpost-emergent applications of various microencapsulated acetochlorformulations as described in Example 2.

FIG. 2 is a graph depicting soybean injury that occurred withpost-emergent applications of various microencapsulated acetochlorformulations as described in Example 2.

FIG. 3 is a graph depicting soybean injury that occurred withpost-emergent applications of various microencapsulated acetochlorformulations as described in Example 2.

FIG. 4 is a graph depicting soybean injury that occurred withpost-emergent applications of various microencapsulated acetochlorformulations as described in Example 2.

FIG. 5 is a graph depicting control of redroot pigweed achieved withpre-emergent applications of various microencapsulated acetochlorformulations as described in Example 2.

FIG. 6 is a graph depicting control of common lambsquarters controlachieved with pre-emergent applications of various microencapsulatedacetochlor formulations as described in Example 2.

FIG. 7 is a graph depicting control of barnyard grass achieved withpre-emergent applications of various microencapsulated acetochlorformulations as described in Example 2.

FIG. 8 is a graph depicting control of yellow foxtail achieved withpre-emergent applications of various microencapsulated acetochlorformulations as described in Example 2.

FIG. 9 is a graph depicting cotton injury that occurred withpost-emergent applications of various microencapsulated acetochlorformulations as described in Example 5.

FIG. 10 is a graph depicting soybean injury that occurred withpost-emergent applications of various microencapsulated acetochlorformulations as described in Example 5.

FIG. 11 is a graph depicting control of redroot pigweed achieved withpre-emergent applications of various microencapsulated acetochlorformulations as described in Example 6.

FIG. 12 is a graph depicting control of common lambsquarters controlachieved with pre-emergent applications of various microencapsulatedacetochlor formulations as described in Example 6.

FIG. 13 is a graph depicting control of barnyard grass achieved withpre-emergent applications of various microencapsulated acetochlorformulations as described in Example 6.

FIG. 14 is a graph depicting control of yellow foxtail achieved withpre-emergent applications of various microencapsulated acetochlorformulations as described in Example 6.

FIG. 15 is a graph depicting control of redroot pigweed achieved withpre-emergent applications of various microencapsulated acetochlorformulations as described in Example 6.

FIG. 16 is a graph depicting control of common lambsquarters controlachieved with pre-emergent applications of various microencapsulatedacetochlor formulations as described in Example 6.

FIG. 17 is a graph depicting control of barnyard grass achieved withpre-emergent applications of various microencapsulated acetochlorformulations as described in Example 6.

FIG. 18 is a graph depicting control of yellow foxtail achieved withpre-emergent applications of various microencapsulated acetochlorformulations as described in Example 6.

FIG. 19 is a graph depicting cotton injury that occurred withpost-emergent applications of various microencapsulated acetochlorformulations as described in Example 10.

FIG. 20 is a graph depicting soybean injury that occurred withpost-emergent applications of various microencapsulated acetochlorformulations as described in Example 10.

FIG. 21 is a graph depicting control of redroot pigweed achieved withpre-emergent applications of various microencapsulated acetochlorformulations as described in Example 10.

FIG. 22 is a graph depicting control of barnyard grass achieved withpre-emergent applications of various microencapsulated acetochlorformulations as described in Example 10.

FIG. 23 is a graph depicting control of yellow foxtail achieved withpre-emergent applications of various microencapsulated acetochlorformulations as described in Example 10.

FIG. 24 is a graph depicting soybean injury that occurred withpost-emergent applications of various microencapsulated acetochlorformulations as described in Example 15.

FIG. 25 is a graph depicting cotton injury that occurred withpost-emergent applications of various microencapsulated acetochlorformulations as described in Example 15.

FIG. 26 is a graph depicting control of redroot pigweed achieved withpre-emergent applications of various microencapsulated acetochlorformulations as described in Example 15.

FIG. 27 is a graph depicting control of common lambsquarters achievedwith pre-emergent applications of various microencapsulated acetochlorformulations as described in Example 15.

FIG. 28 is a graph depicting control of yellow foxtail achieved withpre-emergent applications of various microencapsulated acetochlorformulations as described in Example 15.

FIG. 29 is a graph depicting control of barnyard grass achieved withpre-emergent applications of various microencapsulated acetochlorformulations as described in Example 15.

FIG. 30 is a graph depicting soybean injury that occurred withpost-emergent applications of various microencapsulated acetochlorformulations as described in Example 19.

FIG. 31 is a graph depicting cotton injury that occurred withpost-emergent applications of various microencapsulated acetochlorformulations as described in Example 19.

FIG. 32 is a graph depicting control of redroot pigweed achieved withpre-emergent applications of various microencapsulated acetochlorformulations as described in Example 19.

FIG. 33 is a graph depicting control of barnyard grass achieved withpre-emergent applications of various microencapsulated acetochlorformulations as described in Example 19.

FIG. 34 is a graph depicting control of yellow foxtail achieved withpre-emergent applications of various microencapsulated acetochlorformulations as described in Example 19.

FIG. 35 is a graph depicting soybean injury that occurred withpost-emergent applications of various microencapsulated acetochlorformulations as described in Example 29.

FIG. 36 is a graph depicting cotton injury that occurred withpost-emergent applications of various microencapsulated acetochlorformulations as described in Example 29.

FIG. 37 is a graph depicting control of redroot pigweed achieved withpre-emergent applications of various microencapsulated acetochlorformulations as described in Example 29.

FIG. 38 is a graph depicting control of barnyard grass achieved withpre-emergent applications of various microencapsulated acetochlorformulations as described in Example 29.

FIG. 39 is a graph depicting control of yellow foxtail achieved withpre-emergent applications of various microencapsulated acetochlorformulations as described in Example 29.

FIG. 40 is a graph depicting cotton injury that occurred withpost-emergent applications of various microencapsulated acetochlorformulations as described in Example 30.

FIG. 41 is a graph depicting soybean injury that occurred withpost-emergent applications of various microencapsulated acetochlorformulations as described in Example 30.

FIG. 42 is a graph depicting control of yellow foxtail achieved withpre-emergent applications of various microencapsulated acetochlorformulations as described in Example 30.

FIG. 43 is a graph depicting control of barnyard grass achieved withpre-emergent applications of various microencapsulated acetochlorformulations as described in Example 30.

FIG. 44 is a graph depicting control of redroot pigweed achieved withpre-emergent applications of various microencapsulated acetochlorformulations as described in Example 30.

FIG. 45 is a graph depicting soybean injury that occurred withpost-emergent applications of various microencapsulated acetochlorformulations as described in Example 31.

FIG. 46 is a graph depicting cotton injury that occurred withpost-emergent applications of various microencapsulated acetochlorformulations as described in Example 31.

FIG. 47 is a graph depicting control of yellow foxtail achieved withpre-emergent applications of various microencapsulated acetochlorformulations as described in Example 31.

FIG. 48 is a graph depicting control of barnyard grass achieved withpre-emergent applications of various microencapsulated acetochlorformulations as described in Example 31.

FIG. 49 is a graph depicting control of common purslane achieved withpre-emergent applications of various microencapsulated acetochlorformulations as described in Example 31.

FIG. 50 is a graph depicting control of redroot pigweed achieved withpre-emergent applications of various microencapsulated acetochlorformulations as described in Example 31.

FIG. 51 is a graph depicting soybean injury that occurred withpost-emergent applications of various microencapsulated acetochlorformulations as described in Example 32.

FIG. 52 is a graph depicting cotton injury that occurred withpost-emergent applications of various microencapsulated acetochlorformulations as described in Example 32.

FIG. 53 is a graph depicting cotton injury that occurred withpost-emergent applications of various microencapsulated acetochlorformulations as described in Example 32.

FIG. 54 is a graph depicting soybean injury that occurred withpost-emergent applications of various microencapsulated acetochlorformulations as described in Example 32.

FIG. 55 is a graph depicting control of barnyard grass achieved withpre-emergent applications of various microencapsulated acetochlorformulations as described in Example 32.

FIG. 56 is a graph depicting control of yellow foxtail achieved withpre-emergent applications of various microencapsulated acetochlorformulations as described in Example 32.

FIG. 57 is a graph depicting soybean injury that occurred withpost-emergent applications of various microencapsulated acetochlorformulations as described in Example 33.

FIG. 58 is a graph depicting cotton injury that occurred withpost-emergent applications of various microencapsulated acetochlorformulations as described in Example 33.

FIG. 59 is a graph depicting control of yellow foxtail achieved withpre-emergent applications of various microencapsulated acetochlorformulations as described in Example 33.

FIG. 60 is a graph depicting control of barnyard grass achieved withpre-emergent applications of various microencapsulated acetochlorformulations as described in Example 33.

FIG. 61 is a graph depicting control of perennial ryegrass achieved withpre-emergent applications of various microencapsulated acetochlorformulations as described in Example 33.

FIG. 62 is a graph depicting cotton injury that occurred withpost-emergent applications of various microencapsulated acetochlorformulations as described in Example 37.

FIG. 63 is a graph depicting soybean injury that occurred withpost-emergent applications of various microencapsulated acetochlorformulations as described in Example 37.

FIG. 64 is a graph depicting control of barnyard grass achieved withpre-emergent applications of various microencapsulated acetochlorformulations as described in Example 37.

FIG. 65 is a graph depicting control of yellow foxtail achieved withpre-emergent applications of various microencapsulated acetochlorformulations as described in Example 37.

FIG. 66 is a graph depicting soybean injury that occurred withpost-emergent applications of various microencapsulated acetochlorformulations as described in Example 39.

FIG. 67 is a graph depicting cotton injury that occurred withpost-emergent applications of various microencapsulated acetochlorformulations as described in Example 39.

FIG. 68 is a graph depicting control of barnyard grass achieved withpre-emergent applications of various microencapsulated acetochlorformulations as described in Example 39.

FIG. 69 is a graph depicting control of yellow foxtail achieved withpre-emergent applications of various microencapsulated acetochlorformulations as described in Example 39.

FIG. 70 is a graph depicting cotton injury that occurred withpost-emergent applications of various microencapsulated acetochlorformulations as described in Example 43.

FIG. 71 is a graph depicting control of yellow foxtail achieved withpre-emergent applications of various microencapsulated acetochlorformulations as described in Example 43.

FIG. 72 is a graph depicting control of barnyard grass achieved withpre-emergent applications of various microencapsulated acetochlorformulations as described in Example 43.

FIG. 73 is a graph depicting soybean injury that occurred withpost-emergent applications of various microencapsulated acetochlorformulations as described in Example 48.

FIG. 74 is a graph depicting cotton injury that occurred withpost-emergent applications of various microencapsulated acetochlorformulations as described in Example 48.

FIG. 75 is a graph depicting control of crabgrass achieved withpre-emergent applications of various microencapsulated acetochlorformulations as described in Example 48.

FIG. 76 is a graph depicting control of barnyard grass achieved withpre-emergent applications of various microencapsulated acetochlorformulations as described in Example 48.

FIG. 77 is a graph depicting control of yellow foxtail achieved withpre-emergent applications of various microencapsulated acetochlorformulations as described in Example 48.

FIG. 78 is a graph depicting soybean injury that occurred withpost-emergent applications of various microencapsulated acetochlorformulations as described in Example 49.

FIG. 79 is a graph depicting cotton injury that occurred withpost-emergent applications of various microencapsulated acetochlorformulations as described in Example 49.

FIG. 80 is a graph depicting control of yellow foxtail achieved withpre-emergent applications of various microencapsulated acetochlorformulations as described in Example 49.

FIG. 81 is a graph depicting control of crabgrass achieved withpre-emergent applications of various microencapsulated acetochlorformulations as described in Example 49.

FIG. 82 is a graph depicting control of barnyard grass achieved withpre-emergent applications of various microencapsulated acetochlorformulations as described in Example 49.

FIG. 83 is a graph depicting soybean injury that occurred withpost-emergent applications of various microencapsulated acetochlorformulations as described in Example 52.

FIG. 84 is a graph depicting cotton injury that occurred withpost-emergent applications of various microencapsulated acetochlorformulations as described in Example 52.

FIG. 85 is a graph depicting control of white clover achieved withpre-emergent applications of various microencapsulated acetochlorformulations as described in Example 52.

FIG. 86 is a graph depicting control of crabgrass achieved withpre-emergent applications of various microencapsulated acetochlorformulations as described in Example 52.

FIG. 87 is a graph depicting control of barnyard grass achieved withpre-emergent applications of various microencapsulated acetochlorformulations as described in Example 52.

FIG. 88 is a graph depicting control of yellow foxtail achieved withpre-emergent applications of various microencapsulated acetochlorformulations as described in Example 52.

DESCRIPTION OF THE EMBODIMENTS OF THE INVENTION

In accordance with the present invention, compositions comprisingencapsulated herbicides (e.g., particulate microencapsulated herbicides)having a low initial release rate and a sustained long term release, andmethods for using such compositions, are provided that provide bothcommercially acceptable weed control and commercially acceptable cropinjury. The compositions are useful for the control of weeds,pre-emergence, when applied to fields post-emergence to the crop plants.

In accordance with the present invention, “weed control” refers to anyobservable measure of control of plant growth, which can include one ormore of the actions of (1) killing, (2) inhibiting growth, reproductionor proliferation, and (3) removing, destroying, or otherwise diminishingthe occurrence and activity of plants. Weed control can be measured byany of the various methods known in the art. For example, weed controlcan be determined as a percentage as compared to untreated plantsfollowing a standard procedure wherein a visual assessment of plantmortality and growth reduction is made by one skilled in the artspecially trained to make such assessments. In another controlmeasurement method, control is defined as a mean plant weight reductionpercentage between treated and untreated plants. In yet another controlmeasurement method, control can be defined as the percentage of plantsthat fail to emerge following a pre-emergence herbicide application. A“commercially acceptable rate of weed control” varies with the weedspecies, degree of infestation, environmental conditions, and theassociated crop plant. Typically, commercially effective weed control isdefined as the destruction (or inhibition) of at least about 60%, 65%,70%, 75%, 80%, or even at least 85%, or even at least 90%. Although itis generally preferable from a commercial viewpoint that 80-85% or moreof the weeds be destroyed, commercially acceptable weed control canoccur at much lower destruction or inhibition levels, particularly withsome very noxious, herbicide-resistant plants. Advantageously, theherbicidal microcapsules achieve commercially acceptable weed control inthe time period of from application of the herbicide microcapsules, forexample as contained in an application mixture, to 3 weeks, 4 weeks, 5weeks, 6 weeks, 7 weeks, 8 weeks, 9 weeks, 10 weeks, 11 weeks, or even12 weeks after application of the herbicide microcapsules.

Crop damage can be measured by any means known in the art, such as thosedescribed above for weed control determination. A “commerciallyacceptable rate of crop injury” for the present invention likewisevaries with the crop plant species. Typically, a commercially acceptablerate of crop injury is defined less than about 20%, 15%, 10% or evenless than about 5%. The herbicidal microcapsules of the presentinvention limit crop injury to a commercially acceptable rate asmeasured from about 24 hours (about 1 DAT) after application to twoweeks (about 14 DAT), from about 24 hours (about 1 DAT) afterapplication to three weeks (about 21 DAT), or from about 24 hours (about1 DAT) to about four weeks (about 28 DAT).

In some embodiments of the present invention, the compositions of thepresent invention can be applied post-emergence to crop plants andpre-emergence to weeds in order to simultaneously achieve commercialweed control and a commercially acceptable rate of crop injury. Forpurposes of the present invention, post-emergence to crop plantsincludes initial emergence from the soil, i.e., “at cracking”. Examplesof crop plants include corn, peanuts, potatoes, soybeans, canola,sugarbeets, grain sorghum (milo), field beans and cotton. Crop plantsinclude hybrids, inbreds, and transgenic or genetically modified plantshaving specific traits or combinations of traits including, withoutlimitation, herbicide tolerance (e.g., resistance to glyphosate,glufosinate, sethoxydim, etc.), Bacillus thuringiensis (Bt), high oil,high lysine, high starch, nutritional density, and drought resistance.In some embodiments, the crop plants are resistant to organophosphorusherbicides, ALS inhibitor herbicides, synthetic auxin herbicides and/oracetyl CoA carboxylase inhibitor herbicides, In other embodiments thecrop plants are resistant to glyphosate, dicamba, 2,4-D, MCPA,quizalofop, glufosinate and/or diclofop-methyl. In other embodiments,the crop plant is glyphosate and/or dicamba resistant. In someembodiments of the present invention, crop plants are glyphosate and/orglufosinate resistant. Preferred crops include corn, cotton, andsoybeans. Particularly preferred crop species are cotton and soybean.

Acetamide herbicides suitable for the practice of the present inventioninclude dimethenamid, napropamide, pronamide and acetanilide herbicidessuch as acetochlor, alachlor, butachlor, butenachlor, delachlor,diethatyl, dimethachlor, mefenacet, metazochlor, metolachlor,pretilachlor, propachlor, propisochlor, prynachlor, terbuchlor,thenylchlor and xylachlor, mixtures thereof and stereoisomers thereof.Some acetamide herbicides are available in their free forms, as salts,or as derivatized materials, for example, as esters. Any form of theherbicides described herein by name is potentially applicable. Forinstance, the present invention has utility for both racemic metolachlorand S-metolachlor, and racemic dimethenamid and dimethenamid-P.Preferred acetamide herbicides include dimethenamid and dimethenamid-Pand preferred acetanilide herbicides include acetochlor, metolachlor andS-metolachlor.

An additional aspect of the present invention is the use of theencapsulated acetamide formulations as tank mix partners with foliaractive herbicides. Examples of foliar active herbicides include, but arenot limited to, glyphosate, dicamba, 2,4-D, and/or glufosinate orglufosinate-P. It is well known in the art that the mixing of foliaractive herbicides with co-herbicides (such as acetamides) and/or othermaterials which cause foliar injury can, in some cases, result inantagonism wherein the uptake of the foliar herbicides is reducedthereby resulting in lower herbicidal effectiveness. It is believed thatthe release rate of the encapsulated acetamides of the present inventionis reduced as compared to prior art compositions thereby minimizingantagonism such that the co-herbicide (e.g. glyphosate) is effectivelyabsorbed and translocated within the plant before leaf damage induced bythe acetamide herbicide can significantly interfere with absorption andtranslocation of the co-herbicide. Therefore, in addition to reducingfoliar injury on crop plants, the encapsulated acetamide herbicides ofthis invention should minimize the initial localized foliar injury topreviously emerged weeds and thereby allow the foliar active componentsof the co-herbicide to effectively and efficiently absorb into andtranslocate through the previously emerged weeds in order to achievemaximum activity in the absence of antagonism between the acetamide andco-herbicide.

In general, the encapsulated herbicides of the present invention areprepared by contacting an aqueous continuous phase containing apolyamine component comprising a polyamine source and a discontinuousoil phase containing the herbicide and a polyisocyanate componentcomprising a polyisocyanate source. A shell wall is formed in apolymerization reaction between the polyamine source and the isocyanatesource at the oil/water interface thereby forming a capsule ormicrocapsule containing the herbicide. The polyamine source can be amixture of a principal polyamine and one or more auxiliary polyamines,also termed a polyamine mixture. In some embodiments of the presentinvention, the polyamine source consists essentially of a principalpolyamine. As used herein, a principal polyamine (also referred to as aprincipal amine) refers to a polyamine consisting essentially of asingle polyamine species. The polyisocyanate source can be apolyisocyanate or mixture of polyisocyanates.

In accordance with the present invention and based on experimentalevidence, it has been discovered that the objects of the invention canbe achieved by encapsulating herbicides, in particular, acetamides, inmicrocapsules prepared by the selection of one or more certaincompositional and process variables including the molar ratio ofpolyamine to polyisocyanate, the shell wall composition, the weightratio of core material (herbicide component) to shell wall material, thecore material components, the mean microcapsule particle size, processconditions such as mixing shear and time, and combinations thereof.Through the careful selection of these and other factors, aqueousdispersions of microencapsulated herbicides have been developedaccording to the compositions and methods described herein which, ascompared to compositions and methods known in the art, reduce cropfoliage injury for post-emergent application to the crop plants to acommercially acceptable level while simultaneously achievingcommercially acceptable weed control for pre-emergent application to theweeds. Improved crop safety of the present invention is achieved even inthe absence of a safener.

The microcapsule shell of the present invention may preferably comprisea polyurea polymer formed by a reaction between a principal polyamine,and optionally an auxiliary polyamine, having two or more amino groupsper molecule and at least one polyisocyanate having two or moreisocyanate groups per molecule. Release of the herbicide core materialis controlled by the microcapsule shell wall, preferably without theneed for mechanical release (microcapsule rupture).

In some embodiments, the microcapsules may be prepared by encapsulatingcore material in a shell wall formed by reacting polyamine component anda polyisocyanate component in a reaction medium in concentrations suchthat the reaction medium comprises a molar equivalent excess of aminegroups compared to the isocyanate groups. More particularly, the molarconcentration of amine groups from the principal polyamine and optionalauxiliary polyamine and the molar concentration of isocyanate groupsfrom the at least one polyisocyanate (i.e., one polyisocyanate, a blendof two polyisocyanates, a blend of three polyisocyanates, etc.) in thereaction medium is such that the ratio of the concentration of aminemolar equivalents to the concentration of isocyanate molar equivalentsis at least 1.1:1. The molar ratio of concentration of amine molarequivalents to concentration of isocyanate molar equivalents may becalculated according to the following equation:

$\begin{matrix}{\begin{matrix}{{Molar}\mspace{14mu}{Equivalents}} \\{Ratio}\end{matrix} = \frac{{amine}\mspace{14mu}{molar}\mspace{14mu}{equivalents}}{{polyisocyanate}\mspace{14mu}{molar}\mspace{14mu}{equivalents}}} & (1)\end{matrix}$

In the above equation (1), the amine molar equivalents is calculatedaccording to the following equation:

amine molar equivalents=Σ([polyamine]/equivalent weight).

In the above equation (1), the isocyanate molar equivalents iscalculated according to the following equation:

isocyanate molar equivalents=Σ([polyisocyanate]/equivalent weight)  i.

wherein the polyamine concentration and the polyisocyanate concentrationrefer to the concentration of each in the reaction medium and are eachin grams/L. The equivalent weight is generally calculated by dividingthe molecular weight in grams/mole by the number of functional groupsper molecules and is in grams/mole. For some molecules, such astriethylenetetramine (“TETA”) and 4,4′-diisocyanato-dicyclohexyl methane(“DES W”), the equivalent weight is equal to the molecular weightdivided by the number of functional groups per molecule. For example,TETA has a molecular weight of 146.23 g/mole and 4 amine groups.Therefore, the equivalent weight is 36.6 g/mol. This calculation isgenerally correct, but for some materials, the actual equivalent weightmay vary from the calculated equivalent weight. In some components, forexample, the biuret-containing adduct (i.e., trimer) ofhexamethylene-1,6-diisocyanate, the equivalent weight of thecommercially available material differs from the theoretical equivalentweight due to, for example, incomplete reaction. The theoreticalequivalent weight of the biuret-containing adduct (i.e., trimer) ofhexamethylene-1,6-diisocyanate is 159.5 g/mol. The actual equivalentweight of the trimer of hexamethylene-1,6-diisocyanate (“DES N3200”),the commercially available product, is about 183 g/mol. This actualequivalent weight is used in the calculations above. The actualequivalent weight may be obtained from the manufacturer or by titrationwith a suitable reactant by methods known in the art. The symbol, Σ, inthe amine molar equivalents calculation means that the amine molarequivalents comprises the sum of amine molar equivalents for allpolyamines in the reaction medium. Likewise, the symbol, Σ, in theisocyanate molar equivalents calculation means that the isocyanate molarequivalents comprises the sum of isocyanate molar equivalents for allpolyisocyanates in the reaction medium.

It is advantageous to select a polyamine component and a polyisocyanatecomponent such that the principal polyamine and optional auxiliarypolyamine has an amine functionality of at least 2, i.e., 3, 4, 5 ormore, and at least one of the polyisocyanates has an isocyanatefunctionality of at least 2, i.e., 2.5, 3, 4, 5, or more since highamine and isocyanate functionality increases the percentage ofcross-linking occurring between individual polyurea polymers thatcomprise the shell wall. In some embodiments, the principal polyamineand optional auxiliary polyamine has an amine functionality of greaterthan 2 and the polyisocyanate is a mixture of polyisocyanates whereineach polyisocyanate has an isocyanate functionality of greater than 2.In other embodiments the principal polyamine and optional auxiliarypolyamine comprises a trifunctional polyamine and the polyisocyanatecomponent comprises one or more trifunctional polyisocyanates. In yetother embodiments, the shell wall is formed by the reaction between apolyisocyanate or mixture of polyisocyanates with a minimum average of2.5 reactive groups per molecule and a principal polyamine and optionalauxiliary polyamine with an average of at least three reactive groupsper molecule. It is, moreover, advantageous to select concentrations ofthe polyamine component and the polyisocyanate component such that thepolyisocyanate component is substantially completely reacted to form thepolyurea polymer. Complete reaction of the polyisocyanate componentincreases the percentage of cross-linking between polyurea polymersformed in the reaction thereby providing structural stability to theshell wall. These factors, i.e., the ratio of weight of core materialcomponents compared to weight of shell wall components, the meanparticle sizes of the herbicidal microcapsules, the degree ofcrosslinking, among other factors, may be selected to affect the releaserate profile of the population of herbicidal microcapsules, therebyenabling the preparation of herbicidal microcapsules that balanceenhanced crop safety and are still efficacious for weed control.

Preferably, the molar equivalents ratio of amine molar equivalents toisocyanate molar equivalents is at least about 1.15:1 or even at leastabout 1.20:1. In some embodiments, the molar equivalents ratio is lessthan about 1.7:1, less than about 1.6:1, less than about 1.5:1, lessthan about 1.4:1, or even less than about 1.3:1. In some embodiments,the molar equivalents ratio of amine molar equivalents to isocyanatemolar equivalents in the polymerization medium is from 1.1:1 to about1.7:1, from 1.1:1 to about 1.6:1, from 1.1:1 to about 1.5:1, from 1.1:1to about 1.4:1, from 1.1:1 to about 1.3:1, from about 1.15:1 to about1.7:1, from about 1.15:1 to about 1.6:1, from about 1.15:1 to about1.5:1, from about 1.15:1 to about 1.4:1, or from about 1.15:1 to about1.3:1 Examples of typical ratios include 1.1, 1.15:1, 1.2:1, 1.25:1,1.3:1, 1.35:1, 1.4:1, 1.45:1 and 1.5:1. The molar equivalents ratio usedin the practice of the present invention is greater than that typicallyemployed in prior art compositions wherein a small stoichiometric excessof amine equivalents to isocyanate equivalents of about 1.01:1 to about1.05:1 is used to ensure that the isocyanate is completely reacted. Itis believed, without being bound to any particular theory, thatincreased excess of amine groups used in the present invention resultsin a significant number of unreacted amine functional groups therebyproviding a shell having a large number of amine functional groups thatare not cross-linked. It is believed, that the combination of acompletely reacted and cross-linked polyisocyanate component and anamine component having a significant number of unreacted anduncross-linked functional groups may result in a structurally stableshell wall that is more flexible and/or supple and less likely to shearor rupture as compared to shell walls known in the art. It is furtherbelieved that unreacted amine groups may reduce the number of fissuresor cracks in the shell wall thereby reducing leakage from the core.

In some other embodiments, the concentration of core material incomparison to the concentration of shell wall components in the reactionmedium is controlled thereby resulting in a variation of themicrocapsule shell wall thickness. Preferably, the reaction mediumcomprises core material and shell wall components in a concentration(weight) ratio from about 16:1 to about 3:1, such as from about 13:1 toabout 8:1, from about 13:1 to about 6:1, from about 12:1 to about 6:1,or from about 10:1 to about 6:1. The ratio is calculated by dividing thecore material concentration (grams/L), which consists of the herbicideactive and any diluent solvent or solvents, in the reaction medium bythe concentration of the shell wall components (grams/L) in the reactionmedium. The shell wall components concentrations comprises theconcentration of the polyamine component and the concentration of thepolyisocyanate component. In general, it has been found that decreasingthe ratio of core material to shell wall components tends to reduce, byincrease of shell wall thickness, the release rate of the corematerials. This tends to decrease both the crop injury and weed control,although the amounts of the effects are not always correlated.

In some embodiments, a diluent, such as a solvent, may be added tochange the solubility parameter characteristics of the core material toincrease or decrease the release rate of the active from themicrocapsule, once release has been initiated. For example, the corematerial may comprise from 0% to about 35% by weight of a diluent, forexample from 0.1 to about 25% by weight, from about 0.5% and about 20%by weight, or from about 1% and 10% by weight. In particular, the corematerial may comprise 0%, 0.5% 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 10%, 15%,20%, 25%, 30% or even 35% diluent. In some embodiments, the weight ratioof total core material to diluent can be, for example, from 8 to 1, from10 to 1, from 15 to 1, or from 20 to 1. In some embodiments, the diluentis a water-insoluble organic solvent having a solubility of less than10, 5, 1, 0.5 or even 0.1 gram per liter at 25° C. Examples of suitablewater-insoluble solvents include paraffinic hydrocarbons. Paraffinichydrocarbons are preferably predominantly a linear or branchedhydrocarbon. Examples include pentadecane and ISOPAR V.

A population of herbicidal microcapsules of the present invention may beprepared having at least one mean transverse dimension (e.g., diameteror mean particle size) of at least about 7 micrometers (“microns” orμm). The particle size may be measured with a laser light scatteringparticle size analyzer known to those skilled in the art. One example ofa particle size analyzer is a Coulter LS Particle Size Analyzer. Themicrocapsules are essentially spherical such that the mean transversedimension defined by any point on a surface of the microcapsule to apoint on the opposite side of the microcapsule is essentially thediameter of the microcapsule. Preferably, the population ofmicrocapsules has at least one mean transverse dimension, or meanparticle size, of at least about 7 μm, more preferably at least about 8μm, more preferably at least about 9 μm, more preferably at least about10 μm. In preferred embodiments, the mean particle size of thepopulation of microcapsules is less than about 15 μm, and morepreferably less than 12 μm. In view thereof, a population of herbicidalmicrocapsules of the present invention preferably has a mean particlesize of from about 7 μm to about 15 μm, from about 7 μm to about 12 μm,from about 8 μm to about 12 μm, or from about 9 μm to about 12 μm. Inparticularly preferred embodiments, the range varies from about 9 μm toabout 11 μm.

The particle size of the microcapsules of the present invention arelarger than that typically employed in the art and is generally achievedby varying the composition, as described above, and by controlling thereaction conditions such as, for example, blending speed, shear forces,mixer design and mixing times. In general, reduced blending speed, shearforces and mixing time favor the preparation of larger microcapsules.

In other embodiments of the present invention, two or more of the abovevariables can be manipulated in order to achieve the objects of thepresent invention. Manipulation of the following variable combinationsis within the scope of the present invention: (1) (i) the ratio of molarequivalent amine groups to isocyanate groups and (ii) the weight ratioof the core herbicide to the shell wall components; (2) (i) the ratio ofmolar equivalent amine groups to isocyanate groups and (iii) the weightratio of the core herbicide to the diluent (e.g., solvent); (3) (i) theratio of molar equivalent amine groups to isocyanate groups and (iv) themicrocapsule particle size; (4) (ii) the weight ratio of the coreherbicide to the shell wall components and (iii) the weight ratio of thecore herbicide to the diluent; (5) (ii) the weight ratio of the coreherbicide to the shell wall components and (iv) the microcapsuleparticle size; (6) (iii) the weight ratio of the core herbicide to thediluent and (iv) the microcapsule particle size; (7) (i) the ratio ofmolar equivalent amine groups to isocyanate groups, (ii) the weightratio of the core herbicide to the shell wall components, and (iii) theweight ratio of the core herbicide to the diluent; (8) (i) the ratio ofmolar equivalent amine groups to isocyanate groups, (ii) the weightratio of the core herbicide to the shell wall components, and (iv) themicrocapsule particle size; (9) (i) the ratio of molar equivalent aminegroups to isocyanate groups, (iii) the weight ratio of the coreherbicide to the diluent and (iv) the microcapsule particle size; (10)(ii) the weight ratio of the core herbicide to the shell wallcomponents, (iii) the weight ratio of the core herbicide to the diluentand (iv) the microcapsule particle size; and (11) (i) the ratio of molarequivalent amine groups to isocyanate groups, (ii) the weight ratio ofthe core herbicide to the shell wall components, (iii) the weight ratioof the core herbicide to the diluent and (iv) the microcapsule particlesize.

The release rate of the core material from the microcapsules can becontrolled by selecting capsule properties and composition and byselecting process parameters as previously described. Therefore, byappropriate choice of the parameters discussed previously and below, itis possible to create formulations that have acceptable safety whenapplied as a broadcast spray to a field containing crops after emergenceand maintain good weed control for agriculturally useful lengths oftime.

The microcapsules of the present invention exhibit a release rateprofile that provides a reduced rate of crop injury as compared tomicrocapsules known in the art. Under one theory, and without beingbound to any particular theory, it is believed that increasing the meanparticle size of the population of microcapsules decreases the totaleffective area per unit weight of the microcapsules. Since thediffusional release is proportional to the surface area, this tends, ifeverything else is held constant, to reduce the release rate. This inturn tends to reduce both the weed control and crop injury. However, ithas been surprisingly discovered that the microcapsules of the presentinvention provide initial crop plant injury upon application that iseven less than would be expected based only on a particle size-mediatedrelease rate. It is believed, without being bound to any particulartheory, that the combination of increased particle size and the shellcharacteristics resulting from a large excess of unreacted amine groupssignificantly reduces the amount of herbicide that the crop plants areinitially exposed to upon postemergent application, thereby providingenhanced crop safety and minimized crop plant injury. It is believedthat, as compared to prior art microcapsules, the flexible shell of thepresent invention is resistant to rupturing such that the amount ofherbicide that crop plants are initially exposed to upon application ofa herbicidal formulation containing the microcapsules is reduced.Additionally or alternatively, it is believed that the shell wall of themicrocapsules is characterized by reduced fissuring that decreasesleakage and flow of herbicide through the shell wall. In addition,optimizing the weight ratio of the core to the shell and the weightratio of the core herbicide to the diluent (solvent) may further affectrelease rate and achieve the objects of the present invention.

The release rate profile for the purposes of estimating the potentialfor crop injury of the herbicidal active from a population of herbicidalmicrocapsules of the present invention may be measured in the laboratoryusing an agitated dissolution test apparatus known in the art, such as aSOTAX AT-7 (SOTAX Corporation; Horsham, Pa. 19044) or a HANSON SR8-PLUS(available from Hitachi). In the dissolution rate method protocol of thepresent invention, an aqueous slurry consisting of 1% by weight of theencapsulated acetamide herbicide active ingredient in an aqueous mediumconsisting of deionized water is prepared. For example, a 100 mL aqueousslurry would contain a total of about 1 gram acetamide herbicide. Formicrocapsules comprising 50% by weight acetamide, the aqueous slurrytherefore would contain 2% by weight of the microcapsules. The aqueousslurry is placed a cell of the dissolution test apparatus and agitatedat a temperature of 25° C. The aqueous slurry is agitated at a ratesufficient to maintain the microcapsule particles in suspensionthroughout the test without mechanical rupture of the microcapsuleparticles. For example, in the case of a SOTAX AT-7 agitated dissolutiontest apparatus, the agitator is rotated at about 150 RPM. Aliquots areremoved periodically to determine the concentration of herbicide, e.g.,at 0, 1, 2, 4, 6, and 24 hours. Each aliquot is filtered through asyringe filter (TARGET Cellulose Acetate 0.2 μm, ThermoFisherScientific) to remove any capsules. The resulting solution is thenanalyzed for the active by standard analytical methods known in the art,such as, for instance, HPLC.

According to the method described herein for determining the releaserate profile and based on experimental evidence, it is believed thatgood crop safety correlates to an encapsulated acetamide herbicidecontained with a shell of limited permeability wherein a concentrationof acetamide herbicide (e.g., acetochlor) in the test aliquot at 6 hoursis less than about 100 ppm (about 1% of the total acetamide) and aconcentration of acetamide in the test aliquot at 24 hours is less thanabout 150 ppm (1.5% of the total acetamide. Preferably, theconcentration of acetamide in the test aliquot at 6 hours is less thanabout 75 ppm (0.75% of the total acetamide), and the concentration ofacetamide in the test aliquot at 24 hours is less than about 125 ppm(1.25% of the total acetamide). More preferably, the concentration ofacetamide in the test aliquot at 6 hours is less than about 60 ppm(0.60% of the total acetamide) and less than 100 ppm (1.00% of the totalacetamide) for the test aliquot at 24 hours. Even more preferably, theconcentration of acetamide in the test aliquot at 6 hours is less thanabout 50 ppm (0.50% of the total acetamide) and less than about 75 ppm(0.75% of the total acetamide) in the test aliquot at 24 hours. It hasbeen observed that herbicidal microcapsules having release rate profileswith the above-described parameters generally provide both commerciallyacceptable plant safety and efficacy on weeds. By comparison, a sampleof DEGREE Herbicide, a commercially available microencapsulatedacetochlor formulation available from Monsanto Company, typicallyreleases from about 125 ppm to about 140 ppm in the aliquot at 6 hoursand about 200 ppm (close to saturation) in the aliquot at 24 hours.

Preparation of the encapsulated acetamide herbicides of the presentinvention is described in more detail below.

Acetamide Encapsulation

The polyurea polymer shells of the present invention include a repeatunit having the general structure (I):

wherein X generally represents some portion, or portions, of the repeatunits which, as further defined herein below, may be independentlyselected from a number of different entities (e.g., differenthydrocarbylene linkers, such as aromatic, aliphatic, and cycloaliphaticlinking groups, and moieties having combinations of aromatic, aliphatic,and cycloaliphatic linking groups). The shell encapsulates anacetamide-containing core material such that, once initiated, moleculardiffusion of the acetamide through the shell wall is preferably thepredominant release mechanism (as further described elsewhere herein).Thus, the shell is preferably structurally intact; that is, the shell ispreferably not mechanically harmed or chemically eroded so as to allowthe acetamide to release by a flow mechanism. Further, the shell ispreferably substantially free of defects, such as micropores andfissures, of a size which would allow the core material to be releasedby flow. Micropores and fissures may form if gas is generated during amicrocapsule wall-forming reaction. For example, the hydrolysis of anisocyanate generates carbon dioxide. Accordingly, the microcapsules ofthe present invention are preferably formed in an interfacialpolymerization reaction in which conditions are controlled to minimizethe in situ hydrolysis of isocyanate reactants. The reaction variablesthat may preferably be controlled to minimize isocyanate hydrolysisinclude, but are not limited to: selection of isocyanate reactants,reaction temperature, and reaction in the presence of an excess of aminemolar equivalents over isocyanate molar equivalents.

As used herein, “flow” of the core material from the microcapsulegenerally refers to a stream of the material that drains or escapesthrough a structural opening in the shell wall. In contrast, “moleculardiffusion” generally refers to a molecule of, for example, anacetanilide, which is absorbed into the shell wall at the interiorsurface of the wall and desorbed from the shell wall at the exteriorsurface of the wall.

As described above, the polyurea polymer is preferably the product of areaction between a polyamine component comprising a principal polyamine(and optional auxiliary polyamine) having two or more amino groups permolecule and a poly isocyanate component comprising at least onepolyisocyanate having two or more isocyanate groups per molecule. Insome embodiments, the at least one polyisocyanate comprises a blend oftwo or more polyisocyanates. In some preferred embodiments, the blend ofpolyisocyanates comprises at least one diisocyanate, i.e., having twoisocyanate groups per molecule, and at least one triisocyanate, havingthree isocyanate groups per molecule. Preferably, neither the principalamine nor the auxiliary amine are the product of a hydrolysis reactioninvolving any of the polyisocyanates with which they react to form thepolyurea polymer. More preferably, the shell wall is substantially freeof a reaction product of a polyisocyanate with an amine generated by thehydrolysis of the polyisocyanate. This in situ polymerization of anisocyanate and its derivative amine is less preferred for a variety ofreasons described elsewhere herein.

The shell wall of the microcapsules may be considered “semi-permeable,”which, as used herein, generally refers to a microcapsule having ahalf-life that is intermediate between release from a substantiallyimpermeable microcapsule and a microcapsule that essentially allows theimmediate release of core material (i.e., a microcapsule having ahalf-life of less than about 24 hours, about 18 hours, about 12 hours,or even about 6 hours). For example, a “semi-permeable” microcapsule maya half-life that is from about 5 to about 150 days, about 10 to about125 days, about 25 to about 100 days, or about 50 to about 75 days.

Polyisocyanates

The polyurea polymer shell or wall of the microcapsules may be formedusing one or more polyisocyanates, i.e., having two or more isocyanategroups per molecule. In some embodiments, the polyurea shell wall isformed using a blend of at least two polyisocyanates. In a preferredembodiment, the polyurea shell wall is formed in an interfacialpolymerization reaction using at least one diisocyanate and at least onetriisocyanate.

Polyisocyanates for use in forming the shell wall of the presentinvention have the following general structure (II):

wherein n is an integer that is at least 2, such as from 2 to five, from2 to 4, and preferably is 2 or 3; and R is a group linking the 2 or moreisocyanate groups together, including any aromatic, aliphatic, orcycloaliphatic groups, or combinations of any of aromatic, aliphatic, orcycloaliphatic groups, which are capable of linking the isocyanategroups together.

A wide variety of aliphatic diisocyanates, cycloaliphatic diisocyanates,and aromatic diisocyanates (wherein X is two in structure (II)) may beemployed, for example, diisocyanates containing an aliphatic segmentand/or containing a cycloaliphatic ring segment or an aromatic ringsegment may be employed in the present invention as well.

General aliphatic diisocyanates include those having the followinggeneral structure (III):

O═C═N—(CH₂)_(n)—N═C═O   Structure (III)

where n is an integer having an mean value of from about 2 to about 18,from about 4 to about 16, or about 6 to about 14. Preferably, n is six,i.e., 1,6-hexamethylene diisocyanate. The molecular weight of1,6-hexamethylene diisocyanate is about 168.2 g/mol. Since1,6-hexamethylene diisocyanate comprises 2 isocyanate groups permolecule, its equivalent weight is about 84.1 g/mol. The equivalentweight of the polyisocyanate is generally defined as the molecularweight divided by the number of functional groups per molecule. As notedabove, in some polyisocyanates, the actual equivalent weight may differfrom the theoretical equivalent weight, some of which are identifiedherein.

In certain embodiments, the aliphatic diisocyanates include dimers ofdiisocyanates, for example, a dimer having the following structure (IV):

where n is an integer having an mean value of from about 2 to about 18,from about 4 to about 16, or about 6 to about 14. Preferably, n is six,i.e., structure (IV) is a dimer of 1,6-hexamethylene diisocyanate(molecular weight 339.39 g/mol; equivalent weight=183 g/mol).

A wide variety of cylcoaliphatic and aromatic diisocyanates may be usedas well. In general, aromatic diisocyanates include those diisocynateswherein the R linking group contains an aromatic ring, and acycloaliphatic diisocyanates include those diisocyanates wherein the Rlinking group contains a cylcoaliphatic ring. Typically, the R groupstructure in both aromatic and cycloaliphatic diisocyanates containsmore moieties than just an aromatic or cycloaliphatic ring. Thenomenclature herein is used to classify diisocyanates.

Certain commercially available aromatic diisocyanates comprise twobenzene rings, which may be directly bonded to each other or connectedthrough an aliphatic linking group having from one to about four carbonatoms. One such aromatic diisocyanate is4,4′-diisocyanato-diphenylmethane (bis(4-isocyanatophenyl)methane(Molecular weight=250.25 g/mol; equivalent weight=125 g/mol) having thefollowing structure (V):

Aromatic diisocyanates having structures similar to structure (V)include 2,4′-diisocyanato-diphenylmethane (Molecular weight=250.25g/mol; equivalent weight=125 g/mol) and 2,2′-diisocyanato-diphenylmethane (Molecular weight=250.25 g/mol; equivalent weight=125 g/mol).

Other aromatic diisocyanates, wherein the benzene rings are directlybonded to each other include, 4,4′-diisocyanato-1,1′-biphenyl and4,4′-diisocyanato-3,3′-dimethyl-1,1′-biphenyl (Molecular weight=264.09g/mol; equivalent weight=132 g/mol), which has the following structure(VI):

Yet another aromatic diisocyanate is dianisidine diisocyanate(4,4′-diisocyanato-3,3′-dimethoxybiphenyl) (Molecular weight=296 g/mol;equivalent weight=148 g/mol) having the following structure (VII):

Certain commercially available aromatic diisocyanate comprise a singlebenzene ring. The isocyanate groups may be directly bonded to thebenzene ring or may be linked through aliphatic groups having from oneto about four carbon atoms. An aromatic diisocyanate having a singlebenzene ring is meta-phenylene diisocyanate (1,3-diisocyanatobenzene)(Molecular weight=160.1 g/mol; equivalent weight=80 g/mol) having thestructure (VIII):

Similar aromatic diisocyanates include para-phenylene diisocyanate(Molecular weight=160.1 g/mol; equivalent weight=80 g/mol), 2,4-toluenediisocyanate (2,4-diisocyanato-1-methylbenzene) (Molecular weight=174.2g/mol; equivalent weight=85 g/mol), 2,6-toluene diisocyanate (Molecularweight=174.2 g/mol; equivalent weight=85 g/mol), and2,4,6-triisopropyl-m-phenylene isocyanate. Similar diisocyanates havingaliphatic groups linking the isocyanates to the benzene ring include1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate,tetramethyl-meta-xylylene diisocyanate, tetramethyl-para-xylylenediisocyanate, and meta-tetramethylxylene diisocyanate(1,3-bis(2-isocyanatopropan-2-yl)benzene).

Cycloaliphatic diisocyanate may include one or more cycloaliphatic ringgroups having from four to about seven carbon atoms. Typically, thecycloaliphatic ring is a cyclohexane ring. The one or more cyclohexanerings may be bonded directly to each other or through an aliphaticlinking group having from one to four carbon atoms. Moreover, theisocyanate groups may be directly bonded to the cycloaliphatic ring ormay be linked through an aliphatic group having from one to about fourcarbon atoms. An example of a cycloaliphatic isocyanate is a4,4′-diisocyanato-dicyclohexyl methane(bis(4-isocyanatocyclohexyl)methane) such as Desmodur W (Miles) havingthe structure (IX):

Desmodur W has an approximate molecular weight of 262.35 and anapproximate equivalent weight of 131.2 g/mole. Additional cycloaliphaticdiisocyanates include 1,3-bis(isocyanatomethyl)cyclohexane andisophorone diisocyanate(5-isocyanato-1-(isocyanatomethyl)-1,3,3-trimethylcyclohexane).

Certain aliphatic triisocyanates include, for example, trifunctionaladducts derived from linear aliphatic diisocyanates. The linearaliphatic diisocyanate may have the following structure (III):

O═C═N—(CH₂)_(n)—N═C═O   Structure (III)

where n is an integer having an mean value of from about 2 to about 18,from about 4 to about 16, or about 6 to about 14. A particularlypreferred linear aliphatic diisocyanate of structure (III) useful forpreparing aliphatic triisocyanates is a trimer ofhexamethylene-1,6-diisocyanate. The aliphatic triisocyanates may bederived from the aliphatic isocyanate alone, i.e., dimers, trimers,etc., or they may be derived from a reaction between the aliphaticisocyanate of structure (I), and a coupling reagent such as water or alow molecular weight triol like trimethylolpropane, trimethylolethane,glycerol or hexanetriol.

An exemplary aliphatic triisocyanate, wherein n is 6, is thebiuret-containing adducts (i.e., trimers) ofhexamethylene-1,6-diisocyanate corresponding to the structure (X):

This material is available commercially under the trade name DesmodurN3200 (Miles) or Tolonate HDB (Rhone-Poulenc). Desmodur N3200 has anapproximate molecular weight of 478.6 g/mole. The commercially availableDesmodur N3200 has an approximate equivalent weight of 191 g/mol(Theoretical equivalent weight is 159 g/mol).

Another aliphatic triisocyanate derived from the aliphatic isocyanate ofstructure (III) corresponds to the following general structure:

A specific aliphatic triisocyanate of the above structure wherein the Rgroups are linear hydrocarbons having six carbon atoms (trimers ofhexamethylene-1,6-diisocyanate) having the name HDI isocyanurate trimer,which is available commercially under the trade names Desmodur N3300(Miles) or Tolonate HDT (Rhone-Poulenc). Desmodur N3300 has anapproximate molecular weight of 504.6 g/mol, and an equivalent weight of168.2 g/mol.

Another exemplary aliphatic triisocyanate is the triisocyanate adduct oftrimethylolpropane and hexamethylene-1,6-diisocyanate corresponding tothe structure (XII):

Aromatic triisocyanates containing an aromatic moiety are also useful inthe present invention, including for example those which contain orcomprise polymethylenepolyphenyl polyisocyanate (CAS #9016-87-9,4,4′-(4-isocyanato-1,3-phenylene) bis(methylene) s(isocyanatobenzene))having the structure (XIII):

Isocyanates with an aromatic moiety may have a tendency to undergo insitu hydrolysis at a greater rate than aliphatic isocyanates. Since therate of hydrolysis is decreased at lower temperatures, isocyanatereactants are preferably stored at temperatures no greater than about50° C., and isocyanate reactants containing an aromatic moiety arepreferably stored at temperatures no greater than about 20° C. to about25° C., and under a dry atmosphere.

Still other polyisocyanates include toluene diisocyanate adducts withtrimethylolpropane, xylene diisocyanate and polymethylenepolyphenylpolyisocyanate-terminated polyols.

It is to be noted that selection of the polyisocyanate, or blend ofpolyisocyanates, to be used may be determined experimentally using meansknown in the art (see, e.g., U.S. Pat. No. 5,925,595, the entirecontents of which are incorporated herein for all relevant purposes).Where a blend of a triisocyanate and a diisocyanate is used, the ratioof the triisocyanate to the diisocyanate, on an isocyanate equivalentbasis, is between about 90:10 and about 30:70.

Amines A. Principal Amines

In some preferred embodiments of the present invention, the polyaminecomponent consists essentially of the principal amine. Similarly stated,in some embodiments, the polyamine component is a principal amine in theabsence of one or more auxiliary amines. The polyurea polymers, fromwhich the microcapsule shell wall is prepared or formed, may comprise anamine or polyfunctional amine precursor (e.g., monomer). Among theamines or polyfunctional amines that may be employed to prepare apreferred microcapsule of the present invention are, for example, linearalkylamines or polyalkylamines, having the general structure:

H₂N—X—NH₂   Structure (XIV)

wherein “X” is selected from the group consisting of —(CH₂)_(a)— and—(C₂H₄)—Y—(C₂H₄)—; “a” is an integer having a value from about 1 toabout 8, 2 to about 6, or about 3 to about 5; and, “Y” is selected fromthe group consisting of —S—S—, —(CH₂)_(b)—Z—(CH₂)_(b)—, and—Z—(CH₂)_(a)—Z—, wherein “b” is an integer having a value from 0 to 4,or from 1 to 3, “a” is as defined above, and “Z” is selected from thegroup consisting of

—O—, and —S—.

Examples of such amines or polyfunctional amines that may typically beemployed in the present invention include substituted and unsubstitutedpolyethyleneamines, such as (i) amines of the structureNH₂(CH₂CH₂NH)_(m)CH₂CH₂NH₂ where m is 1 to 5, 1 to 3, or 2, (ii)diethylene triamine (molecular weight=103.17 g/mol, equivalentweight=34.4 g/mol) and (iii) triethylene tetramine (molecularweight=146.23 g/mol, equivalent weight=36.6 g/mol), as well assubstituted and unsubstituted polypropylenimines. However, it is to benoted that other, similar substituted and unsubstituted polyfunctionalamines are also useful, including for example iminobispropylamine,bis(hexamethylene)triamine, cystamine, triethylene glycol diamine (e.g.Jeffamine EDR-148 from Huntsman Corp., Houston, Tex.) and the alkyldiamines, triamine and tetramine having a main alkyl chain of from about2 to about 6, or about 2 to about 4, carbons in length (e.g., fromethylene diamine up to hexamethylene diamine, triamine or tetramine,with a few number of carbons typically being preferred and/or tetraminestypically being preferred over triamines). The principal polyamine maycomprise one or more of any of the above described amines having thegeneral structure (XIV). Among the preferred amines are included, forexample, substituted or unsubstituted polyethyleneamine,polypropyleneamine, diethylene triamine and triethylene tetramine.

B. Auxiliary Amines

In some optional embodiments of the present invention, the polyaminecomponent comprises a principal amine and one or more auxiliary amines.Where the polyamine component comprises a principal amine and anauxiliary amine, the permeability of the shell wall, or the release rateof the core material, may be affected, for example, by varying therelative amounts of 2 or more amines used in the shell wall-formingpolymerization reaction (see, e.g., U.S. Patent Pub. No. 2004/0137031A1, the entire contents of which is incorporated by reference herein).Accordingly, in addition to those principal amines set forth above,auxiliary amines, such as a polyalkyleneamine or an epoxy-amine adduct,may be optionally included in combination with the principal amine toprovide microcapsules having an altered shell wall permeability orrelease rate as compared to a shell wall prepared from an amine sourceconsisting essentially of a principal amine, in addition to thepermeability imparted thereto upon activation of the microcapsule (e.g.,by cleavage of the blocking group from the polymer backbone).

This permeability, or release rate, may change (e.g., increase) as theratio of the auxiliary amine to a principal amine increases. It is to benoted, however, that alternatively or additionally, as described ingreater detail elsewhere herein, the rate of permeability may be furtheroptimized by altering the shell wall composition by, for example, (i)the type of isocyanate employed, (ii) using a blend of isocyanates,(iii) using an amine having the appropriate hydrocarbon chain lengthbetween the amino groups, and/or (iv) varying the ratios of the shellwall components and core components, all as determined, for example,experimentally using means standard in the art.

In some embodiments, the permeability-altering or auxiliary amine may bea polyalkyleneamine prepared by reacting an alkylene oxide with a diolor triol to produce a hydroxyl-terminated polyalkylene oxideintermediate, followed by amination of the terminal hydroxyl groups.

Alternatively, the auxiliary amine may be a polyetheramine(alternatively termed a polyoxyalkyleneamine, such as for examplepolyoxypropylenetri- or diamine, and polyoxyethylenetri- or diamine)having the following structure (XV):

wherein: c is a number having a value of 0 or 1; “R¹” is selected fromthe group consisting of hydrogen and CH₃(CH₂)_(d)—; “d” is a numberhaving a value from 0 to about 5; “R²” and “R³” are

respectively; “R⁴” is selected from the group consisting of hydrogenand;

wherein “R⁵”, “R⁶”, and “R⁷” are independently selected from a groupconsisting of hydrogen, methyl, and ethyl; and, “x”, “y”, and “z” arenumbers whose total ranges from about to 2 to about 40, or about 5 toabout 30, or about 10 to about 20.

In some embodiments, the value of x+y+z is preferably no more than about20, or more preferably no more than about 15 or even about 10. Examplesof useful auxiliary amine compounds having this formula include aminesof the Jeffamine ED series (Huntsman Corp., Houston, Tex.). One of suchpreferred amines is Jeffamine T-403 (Huntsman Corp., Houston, Tex.),which is a compound according to this formula wherein c, g and h areeach 0, R1 is CH₃CH₂ (i.e., CH₃(CH₂)d, where d is 1), R₅, R₆, and R₇ areeach a methyl group and the average value of x+y+z is from about 5 andabout 6.

The reaction of a polyfunctional amine with an epoxy functional compoundhas been found to produce epoxy-amine adducts which are also useful asauxiliary amines. Epoxy-amine adducts are generally known in the art.(See, e.g., Lee, Henry and Neville, Kris, Aliphatic Primary Amines andTheir Modifications as Epoxy-Resin Curing Agents in Handbook of EpoxyResins, pp. 7-1 to 7-30, McGraw-Hill Book Company (1967).) Preferably,the adduct has a water solubility as described for amines elsewhereherein. Preferably, the polyfunctional amine which is reacted with anepoxy to form the adduct is an amine as previously set forth above. Morepreferably, the polyfunctional amine is diethylenetriamine orethylenediamine. Preferred epoxies include ethylene oxide, propyleneoxide, styrene oxide, and cyclohexane oxide. Diglycidyl ether ofbisphenol A (CAS #1675-54-3) is a useful adduct precursor when reactedwith an amine in an amine to epoxy group ratio preferably of at leastabout 3 to 1.

It is to be noted, however, that permeability may also be decreased insome instances by the addition of an auxiliary amine. For example, it isknown that the selection of certain ring-containing amines as thepermeability-altering or auxiliary amine is useful in providingmicrocapsules with release rates which decrease as the amount of such anamine increases, relative to the other, principal amine(s) therein.Preferably, the auxiliary amine is a compound selected from the groupconsisting of cycloaliphatic amines and arylalkyl amines. Aromaticamines, or those having the nitrogen of an amine group bonded to acarbon of the aromatic ring, may not be universally suitable. Exemplary,and in some embodiments preferred, cycloaliphatic amines include4,4′-diaminodicyclohexyl methane, 1,4-cyclohexanebis(methylamine) andisophorone diamine (5-Amino-1,3,3-trimethylcyclohexanemethylamine;molecular weight=170.30 g/mol; equivalent weight=85.2 g/mol). Exemplary,and in some embodiments preferred, arylalkyl amines have the structureof the following structure (XVI):

wherein “e” and “f” are integers with values which independently rangefrom about 1 to about 4, or about 2 to about 3. Meta-xylylene diamine,from Mitsubishi Gas Co., Tokyo, JP, is a preferred example of anarylalkyl amine (molecular weight=136.19 g/mol; equivalent weight=68.1g/mol). Another example is para-xylylenediamine. Alkyl substitutedarylalkyl polyamines include 2,3,5,6-tetramethyl-1,4-xylylenediamine and2,5-dimethyl-1,4-xylylenediamine.

C. Amine Properties

Preferably, the principal amine (and optional auxiliary polyamine) hasat least about two amino groups or functionalities, and even morepreferably, the amine comprises at least three amino groups. Withoutbeing held to any particular theory, it is generally believed that in aninterfacial polymerization as described herein, the effectivefunctionality of a polyfunctional amine is typically limited to onlyslightly higher than about 2 and less than about 4. This is believed tobe due to steric factors, which normally prevent significantly more thanabout 3 amino groups in the polyfunctional amine shell wall precursorfrom participating in the polymerization reaction.

It is to be further noted that the molecular weight of the aminemonomer, which may or may not possess an amine blocking group thereon,is preferably less than about 1000 g/mole, and in some embodiments ismore preferably less than about 750 g/mole or even 500 g/mole. Forexample, the molecular weight of the amine monomer, which may or may nothave one or more block amine functionalities therein, may range fromabout 75 g/mole to less than about 750 g/mole, or from about 100 g/moleto less than about 600 g/mole, or from about 150 g/mole to less thanabout 500 g/mole. Equivalent weights (the molecular weight divided bythe number of amine functional groups) generally range from about 20g/mole to about 250 g/mole, such as from about 30 g/mole to about 125g/mole. Without being held to a particular theory, it is generallybelieved that steric hindrance is a limiting factor here, given thatbigger molecules may not be able to diffuse through the early-formingproto-shell wall to reach, and react to completion with, the isocyanatemonomer in the core during interfacial polymerization.

Core Material Composition

Generally speaking, useful herbicidal core materials include those thatare a single phase liquid at temperatures of less than about 80° C.Preferably, the core material is a liquid at temperatures of less thanabout 65° C. More preferably, the core material is a liquid attemperatures of less than about 50° C. The core material may alsocomprise solids suspended in a liquid phase. Whether liquid or solids ina liquid phase, the core material preferably has a viscosity such thatit flows easily to facilitate transport by pumping and to facilitate thecreation of an oil in water emulsion as part of the method forpreparation of microcapsules discussed herein. Thus, the core materialpreferably has a viscosity of less than about 1000 centipoise (cps)(e.g., less than about 900, 800, 700, 600 or even 500 cps) at thetemperature at which the emulsion is formed and the polymerizationreaction occurs, typically from about 25° C. to about 65° C., typically,from about 40° C. to about 60° C. Preferably, the core material iswater-immiscible, a property which promotes encapsulation by interfacialpolymerization. Water-immiscibility refers to materials that have arelatively low water solubility at about 25° C., for example, less thanabout 500 mg/L, preferably less than about 250 mg/L, even morepreferably less than about 100 mg/L. Certain core materials have evenlower water solubilities, such as acetochlor, which is less than 25 mg/Lat 25° C. In some preferred embodiments, the acetamide herbicidal corematerials suitable for the practice of the present invention includedimethenamid, napropamide, pronamide and acetanilide herbicides such asacetochlor, alachlor, butachlor, butenachlor, delachlor, diethatyl,dimethachlor, mefenacet, metazochlor, metolachlor, pretilachlor,propachlor, propisochlor, prynachlor, terbuchlor, thenylchlor andxylachlor, mixtures thereof and stereoisomers thereof. Preferredacetamide herbicides include dimethenamid and dimethenamid-P andpreferred acetanilide herbicides include acetochlor, metolachlor andS-metolachlor.

The core material may comprise multiple compounds for release (e.g., anacetamide and one or more additives compatible therewith which act toenhance its bioefficacy on weeds and/or reduce crop injury). Forexample, in some embodiments, the core material optionally comprises asafener. Suitable safeners include, for example, furilazole((RS)-3-(dichloroacetyl)-5-(2-furanyl)-2,2-dimethyl-1,3-oxazolidine95%), commercially available from Monsanto Company; AD 67(4-(dichloroacetyl)-1-oxa-4-azaspiro[4, 5]decane); benoxacor (CGA154281, (RS)-4-dichloroacetyl-3,4-dihydro-3-methyl-2H-1,4-benzoxazine);cloquintocet-mexyl (CGA 184927, (5-chloroquinolin-8-yloxy)acetic acid);cyometrinil (CGA 43089, (Z)-cyanomethoxyimino(phenyl)acetonitrile);cyprosulfamide (N-[4-(cyclopropylcarbamoyl)phenylsulfonyl]-o-anisamide);dichlormid (DDCA, R25788, N, N-diallyl-2, 2-dichloroacetamide);dicyclonon((RS)-1-dichloroacetyl-3,3,8a-trimethylperhydropyrrolo[1,2-a]pyrimidin-6-one);dietholate (O,O-diethyl O-phenyl phosphorothioate) fenchlorazole-ethyl(HOE 70542,1-(2,4-dichlorophenyl)-5-trichloromethyl-1H-1,2,4-triazole-3-carboxylicacid); fenclorim (CGA 123407 4, 6-dichloro-2-phenylpyrimidine);flurazole (benzyl2-chloro-4-trifluoromethyl-1,3-thiazole-5-carboxylate); fluxofenim (CGA133205, 4′-chloro-2,2,2-trifluoroacetophenone(EZ)—O-1,3-dioxolan-2-ylmethyloxime); isoxadifen(4,5-dihydro-5,5-diphenyl-1,2-oxazole-3-carboxylic acid); mefenpyr((RS)-1-(2,4-dichlorophenyl)-5-methyl-2-pyrazoline-3,5-dicarboxylicacid); mephenate (4-chlorophenyl methylcarbamate); MG 191; naphthalicanhydride; oxabetrinil (CGA 92194,(Z)-1,3-dioxolan-2-ylmethoxyimino(phenyl)acetonitrile); and others asare known in the art. It is to be noted that the herbicidalmicrocapsules, through selection of processing and structuralparameters, achieve commercially acceptable crop safety even in theabsence of a safener. Therefore, the safener is an optional corematerial.

It is to be further noted, as previously described, that the corematerial may optionally comprise a diluent. The diluent may be added tochange the solubility parameter characteristics of the core material toincrease or decrease the release rate of the active from themicrocapsule, once release has been initiated. The preferred diluentcontent in the core material is as previously described.

The diluent may be selected from essentially any of those known in theart. The compatibility of the diluent with the core material (e.g., theacetamide active) and/or the shell wall may be determined, for example,experimentally using means standard in the art (see, e.g., U.S. PatentPub. No. 2004/0137031 A1 and U.S. Pat. No. 5,925,595, the entirecontents of which are incorporated herein for all relevant purposes).Exemplary diluents include, for example: alkyl-substituted biphenylcompounds (e.g., SureSol 370, commercially available from Koch Co.);normal paraffin oil (e.g., NORPAR 15, commercially available fromExxon); mineral oil (e.g., ORCHEX 629, commercially available fromExxon); isoparaffin oils (e.g., ISOPAR V and ISOPAR L, commerciallyavailable from Exxon); aliphatic fluids or oils (e.g., EXXSOL D110 andEXXSOL D130, commercially available from Exxon); alkyl acetates (e.g.,EXXATE 1000, formerly commercially available from Exxon); aromaticfluids or oils (A 200, commercially available from Exxon); citrateesters (e.g., Citroflex A4, commercially available from Morflex); and,plasticizing fluids or oils used in, for examples, plastics (typicallyhigh boiling point esters).

Preparation of Microcapsules and Dispersions Thereof

In general, an aqueous dispersion of the microcapsules of the presentinvention may be produced by an interfacial polymerization reaction,either continuously or batchwise, using means generally known in theart. However, preferably a principal amine is polymerized with one ormore polyisocyanates at the interface of an oil-in-water emulsion. Thediscontinuous oil phase (also referred to herein as “internal phase”)preferably comprises one or more polyisocyanates and a continuousaqueous phase (also referred to herein as “external phase”) comprisesthe principal amine. The oil phase further comprises a core materialthat preferably comprises an acetamide herbicide as the activeingredient. In other embodiments, when more than one amine is used(e.g., a principal amine and an auxiliary amine), these amines may bereacted in a ratio such that the microcapsules have a predeterminedpermeability with respect to the core material, either prior toactivation or additionally upon activation.

In this regard it is to be noted that preferably the amine is not thehydrolysis product of the isocyanate. Rather, it is preferred that thereactants are selected from, for example, the amines and polyisocyanatesdisclosed elsewhere herein.

The oil-in-water emulsion is preferably formed by adding the oil phaseto the continuous aqueous phase to which an emulsifying agent has beenadded (e.g., previously dissolved therein). The emulsifying agent isselected to achieve the desired oil droplet size in the emulsion. Thesize of the oil droplets in the emulsion is impacted by a number offactors in addition to the emulsifying agent employed and determines thesize of microcapsules formed by the process, as described elsewhereherein. The emulsifying agent is preferably a protective colloid.Polymeric dispersants are preferred as protective colloids. Polymericdispersants provide steric stabilization to an emulsion by adsorbing tothe surface of an oil drop and forming a high viscosity layer whichprevents drops from coalescing. Polymeric dispersants may be surfactantsand are preferred to surfactants which are not polymeric, becausepolymeric compounds form a stronger interfacial film around the oildrops. If the protective colloid is ionic, the layer formed around eachoil drop will also serve to electrostatically prevent drops fromcoalescing. SOKALAN (BASF), a maleic acid-olefin copolymer, is apreferred protective colloid, as is Invalon and Lomar D (Cognis).

Other protective colloids useful in this invention are gelatin, casein,polyvinyl alcohol, alkylated polyvinyl pyrrolidone polymers, maleicanhydride-methyl vinyl ether copolymers, styrene-maleic anhydridecopolymers, maleic acid-butadiene and diisobutylene copolymers, sodiumand calcium lignosulfonates, sulfonated naphthalene-formaldehydecondensates, modified starches, and modified cellulosics likehydroxyethyl or hydroxypropyl cellulose, and carboxy methyl cellulose.

To prepare microcapsules of a preferred mean diameter, the selection ofa protective colloid and the conditions of the emulsification step areto be given consideration. For example, the quality of the emulsion, andhence the size of the microcapsules produced, is dependent to someextent upon the stirring operation used to impart mechanical energy tothe emulsion. Preferably, the emulsification is accomplished with a highshear disperser. Generally, the microcapsules produced by this processhave a size roughly approximated by the size of the oil drops from whichthey formed. Therefore, the emulsion is typically mixed to create oildrops having a mean diameter preferably at least about 5 μm, buttypically less than about 15 μm.

The time that the emulsion remains in a high shear mixing zone ispreferably limited to only the time required to create an emulsionhaving the desired droplet size. The longer the emulsion remains in thehigh shear mixing zone, the greater the degree to which thepolyisocyanate will hydrolyze and react in situ. A consequence of insitu reaction is the premature formation of shell walls. Shell wallsformed in the high shear zone may be destroyed by the agitationequipment, resulting in wasted raw materials and an unacceptably highconcentration of unencapsulated core material in the aqueous phase.Typically, mixing the phases with a Waring blender for about 45 secondsto about 90 seconds, or with an in-line rotor/stator disperser having ashear zone dwell time of much less than a second, is sufficient. Aftermixing, the emulsion is preferably agitated sufficiently to maintain avortex.

The time at which the amine source is added to the aqueous phase is aprocess variable that may affect, for example, the size distribution ofthe resulting microcapsules and the degree to which in situ hydrolysisoccurs. Contacting the oil phase with an aqueous phase which containsthe amine source prior to emulsification initiates some polymerizationat the oil/water interface. If the mixture has not been emulsified tocreate droplets having the preferred size distribution, a number ofdisfavored effects may result, including but not limited to: thepolymerization reaction wastefully creates polymer which is notincorporated into shell walls; oversized microcapsules are formed; or,the subsequent emulsification process shears apart microcapsules whichhave formed.

In some instances, the negative effects of premature amine addition maybe avoided by adding a non-reactive form of the amine to the aqueousphase and converting the amine to its reactive form after emulsion. Forexample, the salt form of amine reactants may be added prior toemulsification and thereafter converted to a reactive form by raisingthe pH of the emulsion once it is prepared. This type of process isdisclosed in U.S. Pat. No. 4,356,108, which is herein incorporated byreference in its entirety. However, it is to be noted that the increasein pH required to activate amine salts may not exceed the tolerance ofthe protective colloid to pH swings, otherwise the stability of theemulsion may be compromised.

Accordingly, it may be preferable for the amine source to be added afterthe preparation of the emulsion. More preferably, the amine source maybe added as soon as is practical after a suitable emulsion has beenprepared. Otherwise, the disfavored in situ hydrolysis reaction may befacilitated for as long as the emulsion is devoid of amine reactant,because the reaction of isocyanate with water proceeds unchecked by anypolymerization reaction with amines. Therefore, amine addition ispreferably initiated and completed as soon as practical after thepreparation of the emulsion.

There may be, however, situations where it is desirable to purposefullyincrease the period over which the amine source is added. For example,the stability of the emulsion may be sensitive to the rate at which theamine is added. Alkaline colloids, like SOKALAN, can generally handlethe rapid addition of amines. However, rapid addition of amines to anemulsion formed with non-ionic colloids or PVA cause the reactionmixture to gel rather than create a dispersion. Furthermore, ifrelatively “fast reacting” polyisocyanates are used (e.g.,polyisocyanates containing an aromatic moiety), gelling may also occurif the amines are added too quickly. Under the above circumstances, itis typically sufficient to extend the addition of the amine over aperiod of from about 3 to about 15 minutes, or from about 5 to about 10minutes. The addition is still preferably initiated as soon as ispractical after the emulsion has been prepared.

The viscosity of the external phase is primarily a function of theprotective colloid present. The viscosity of the external phase ispreferably less than about 50 cps, more preferably less than about 25cps, and still more preferably less than about 10 cps at the temperatureof emulsion preparation, which is typically from about 25° C. to about65° C., preferably from about 40° C. to about 60° C. The external phaseviscosity is measured with a Brookfield viscometer with a spindle size 1or 2 and at about 20 to about 60 rpm speed. After reaction and withoutadditional formulation, the microcapsule dispersion which is prepared bythis process preferably has a viscosity of less than about 400 cps(e.g., less than about 350 cps, about 300 cps, about 250 cps, or evenabout 200 cps) at the temperature of emulsion preparation. Morepreferably the dispersion viscosity is from about 100 to about 200 cps,or from 125 to about 175 cps at the temperature of emulsion preparation.

It is preferred that the oil phase is in the liquid state as it isblended into the aqueous phase. Preferably, the acetamide herbicide orother active ingredient is melted or dissolved or otherwise prepared asliquid solution prior to the addition of the isocyanate reactant. Tothese ends, the oil phase may require heating during its preparation.

The discontinuous oil phase may also be a liquid phase which containssolids. Whether liquid, low melting solid, or solids in a liquid, thediscontinuous oil phase preferably has a viscosity such that it flowseasily to facilitate transport by pumping and to facilitate the creationof the oil-in-water emulsion. Thus, the discontinuous oil phasepreferably has a viscosity of less than about 1000 cps (e.g., less thanabout 900 cps, about 800 cps, about 700 cps, about 600 cps, or evenabout 500 cps) at the temperature of emulsion preparation, which istypically from about 25° C. to about 65° C., preferably from about 40°C. to about 60° C.

To minimize isocyanate hydrolysis and in situ shell wall formation, acooling step subsequent to heating the oil phase is preferred when theoil phase comprises a polyisocyanate comprising an aromatic moiety,because isocyanates comprising an aromatic moiety undergo thetemperature-dependent hydrolysis reaction at a faster rate thannon-aromatic isocyanates. It has been discovered that the hydrolysisreaction has a negative effect on the preparation of the microcapsulesof the present invention. Among other problems, isocyanates hydrolyze toform amines that compete in situ with the selected amine in thepolymerization reaction, and the carbon dioxide generated by thehydrolysis reaction may introduce porosity into the preparedmicrocapsules. Therefore, it is preferred to minimize the hydrolysis ofisocyanate reactants at each step of the process of the presentinvention. Since the hydrolysis reaction rate is directly dependent onthe temperature, it is particularly preferred that the internal phase(i.e., discontinuous phase) be cooled to less than about 50° C.subsequent to mixing the polyisocyanate and the core material. It isalso preferred that the internal phase be cooled to less than about 25°C. if isocyanates comprising an aromatic moiety are used.

Hydrolysis may also be minimized by avoiding the use of oil phasecompositions in which water is highly soluble. Preferably water is lessthan about 5% by weight soluble in the oil phase at the temperature ofthe emulsion during the reaction step. More preferably water is lessthan about 1% soluble in the oil phase. Still more preferably water isless than about 0.1% soluble in the oil phase. It is preferred that theoil phase has a low miscibility in water. Low miscibility in water alsopromotes the formation of a useful emulsion.

It is preferred that the principal polyamine (and optional auxiliarypolyamine) is sufficiently mobile across an oil-water emulsioninterface. Thus, it is preferred that amines selected for thewall-forming reaction have an n-octanol/water partition coefficientwherein the base-10 log of the partition coefficient is between about −4and about 1. It is also preferred that the reaction occur on the oilside of the oil-water interface, but is it believed that at partitioncoefficient values lower than about −4 the amines may not be solubleenough in the oil phase to participate sufficiently in the wall-formingreaction. Therefore, the reaction may proceed too slowly to beeconomical, or the disfavored in situ reaction may predominate.Furthermore, at partition coefficient values above about 1, the aminesmay not be sufficiently soluble in the water phase to be evenlydistributed enough throughout the aqueous phase to facilitate aconsistent reaction rate with all the oil particles. Therefore, morepreferably the base-10 log of the partition coefficient is between about−3 and about 0.25, or about −2 and about 0.1.

To further reduce the amount of poyisocyanate hydrolysis and in situreaction, the reaction is preferably run at as low of a temperature aseconomics based on the reaction rate will allow. For example, thereaction step may preferably be performed at a temperature from about40° C. to about 65° C. More preferably, the reaction step may beperformed at a temperature from about 40° C. to about 50° C.

The reaction step may preferably be performed to convert at least about90% of the polyisocyanate. The reaction step may more preferably beperformed to convert at least about 95% of the polyisocyanate. In thisregard it is to be noted that the conversion of polyisocyanate may betracked by monitoring the reaction mixture around an isocyanate infraredabsorption peak at 2270 cm⁻¹, until this peak is essentially no longerdetectable. The reaction may achieve 90% conversion of the isocyanate ata reaction time which is within the range of, for example, aboutone-half hour to about 3 hours, or about 1 to about 2 hours, especiallywhere the core material comprises an acetanilide.

Liquid Microcapsule Dispersions: Parameters and Compositions

The microcapsules of the present invention comprise a water-immiscible,agricultural chemical-containing core material encapsulated by apolyurea shell wall, which is preferably substantially non-microporous,such that core material release occurs by a molecular diffusionmechanism, as opposed to a flow mechanism through a pore or rift in thepolyurea shell wall. As noted herein, the shell wall may preferablycomprise a polyurea product of a polymerization of one or morepolyisocyanates and a principal polyamine (and optional auxiliarypolyamine). Additionally, a further embodiment of the present inventioncomprises a liquid dispersion of the microcapsules of the presentinvention. The liquid medium in which the microcapsules are dispersed ispreferably aqueous (e.g., water). The dispersion may optionally, and/orpreferably, be further formulated with additives as described elsewhereherein (e.g., a stabilizer, one or more surfactants, an antifreeze, ananti-packing agent, drift control agents, etc.).

The aqueous dispersion of microcapsules of the present invention maypreferably be formulated to further optimize its shelf stability andsafe use. Dispersants and thickeners are useful to inhibit theagglomeration and settling of the microcapsules. This function isfacilitated by the chemical structure of these additives as well as byequalizing the densities of the aqueous and microcapsule phases.Anti-packing agents are useful when the microcapsules are to beredispersed. A pH buffer can be used to maintain the pH of thedispersion in a range which is safe for skin contact and, depending uponthe additives selected, in a narrower pH range than may be required forthe stability of the dispersion.

Low molecular weight dispersants may solubilize microcapsule shellwalls, particularly in the early stages of their formation, causinggelling problems. Thus, in some embodiments dispersants havingrelatively high molecular weights of at least about 1.5 kg/mole, morepreferably of at least about 3 kg/mole, and still more preferably atleast about 5, 10 or even 15 kg/mole. In some embodiments, the molecularweight may range from about 5 kg/mole to about 50 kg/mole. Dispersantsmay also be non-ionic or anionic. An example of a high molecular weight,anionic polymeric dispersant is polymeric naphthalene sulfonate sodiumsalt, such as Invalon (formerly Irgasol, Huntsman Chemicals). Otheruseful dispersants are gelatin, casein, ammonium caseinate, polyvinylalcohol, alkylated polyvinyl pyrrolidone polymers, maleicanhydride-methyl vinyl ether copolymers, styrene-maleic anhydridecopolymers, maleic acid-butadiene and diisobutylene copolymers, sodiumand calcium lignosulfonates, sulfonated naphthalene-formaldehydecondensates, modified starches, and modified cellulosics likehydroxyethyl or hydroxypropyl cellulose, and sodium carboxy methylcellulose.

Thickeners are useful in retarding the settling process by increasingthe viscosity of the aqueous phase. Shear-thinning thickeners may bepreferred, because they act to reduce dispersion viscosity duringpumping, which facilitates the economical application and even coverageof the dispersion to an agricultural field using the equipment commonlyemployed for such purpose. The viscosity of the microcapsule dispersionupon formulation may preferably range from about 100 cps to about 400cps, as tested with a Haake Rotovisco Viscometer and measured at about10° C. by a spindle rotating at about 45 rpm. More preferably, theviscosity may range from about 100 cps to about 300 cps. A few examplesof useful shear-thinning thickeners include water-soluble, guar- orxanthan-based gums (e.g. Kelzan from CPKelco), cellulose ethers (e.g.ETHOCEL from Dow), modified cellulosics and polymers (e.g. Aqualonthickeners from Hercules), and microcrystalline cellulose anti-packingagents.

Adjusting the density of the aqueous phase to approach the mean weightper volume of the microcapsules also slows down the settling process. Inaddition to their primary purpose, many additives may increase thedensity of the aqueous phase. Further increase may be achieved by theaddition of sodium chloride, glycol, urea, or other salts. The weight tovolume ratio of microcapsules of preferred dimensions is approximated bythe density of the core material, where the density of the core materialis from about 1.05 to about 1.5 g/cm³. Preferably, the density of theaqueous phase is formulated to within about 0.2 g/cm³ of the mean weightto volume ratio of the microcapsules. More preferably, the density ofthe aqueous phase ranges from about 0.2 g/cm³ less than the weight meanweight to volume ratio of the microcapsules to about equal to the weightmean weight to volume ratio of the microcapsules.

Surfactants can optionally be included in the formulated microcapsuledispersions of the present invention. Suitable surfactants are selectedfrom non-ionics, cationics, anionics and mixtures thereof. Examples ofsurfactants suitable for the practice of the present invention include,but are not limited to: alkoxylated tertiary etheramines (such as TOMAHE-Series surfactants); alkoxylated quaternary etheramine (such as TOMAHQ-Series surfactant); alkoxylated etheramine oxides (such as TOMAHAO-Series surfactant); alkoxylated tertiary amine oxides (such as AROMOXseries surfactants); alkoxylated tertiary amine surfactants (such as theETHOMEEN T and C series surfactants); alkoxylated quaternary amines(such as the ETHOQUAD T and C series surfactants); alkyl sulfates, alkylether sulfates and alkyl aryl ether sulfates (such as the WITCOLATEseries surfactants); alkyl sulfonates, alkyl ether sulfonates and alkylaryl ether sulfonates (such as the WITCONATE series surfactants);alkoxylated phosphate esters and diesters (such as the PHOSPHOLAN seriessurfactants); alkyl polysaccharides (such as the AGRIMUL PG seriessurfactants); alkoxylated alcohols (such as the BRIJ or HETOXOL seriessurfactants); and mixtures thereof.

Anti-packing agents facilitate redispersion of microcapsules uponagitation of a formulation in which the microcapsules have settled. Amicrocrystalline cellulose material such as LATTICE from FMC iseffective as an anti-packing agent. Other suitable anti-packing agentsare, for example, clay, silicon dioxide, insoluble starch particles, andinsoluble metal oxides (e.g. aluminum oxide or iron oxide). Anti-packingagents which change the pH of the dispersion are preferably avoided, forat least some embodiments.

Drift control agents suitable for the practice of the present inventionare known to those skilled in the art and include the commercialproducts GARDIAN, GARDIAN PLUS, DRI-GARD, PRO-ONE XL ARRAY, COMPADRE,IN-PLACE, BRONC MAX EDT, EDT CONCENTRATE, COVERAGE and BRONC Plus DryEDT.

The formulated microcapsule dispersions of the present invention arepreferably easily redispersed, so as to avoid problems associated withapplication (e.g., clogging a spray tank). Dispersability may bemeasured by the Nessler tube test, wherein Nessler tubes are filled with95 ml of water, then 5 ml of the test formulation is added by syringe.The tube is stoppered, and inverted ten times to mix. It is then placedin a rack, standing vertically, for 18 hours at 20° C. The tubes areremoved and smoothly inverted every five seconds until the bottom of thetube is free of material. The number of inversions required to remix thesettled material from the formulation is recorded. Preferably, thedispersions of the present invention are redispersed with less thanabout 100 inversions as measured by a Nessler tube test. Morepreferably, less than about 20 inversions are required for redispersion.

The pH of the formulated microcapsule dispersion may preferably rangefrom about 4 to about 9, in order to minimize eye irritation of thosepersons who may come into contact with the formulation in the course ofhandling or application to crops. However, if components of a formulateddispersion are sensitive to pH, such as for example the blocking agent,buffers such as disodium phosphate may be used to hold the pH in a rangewithin which the components are most effective. Additionally, a pHbuffer such as citric acid monohydrate may be particularly useful insome systems during the preparation of microcapsules, to maximize theeffectiveness of a protective colloid such as SOKALAN CP9.

Other useful additives include, for example, biocides or preservatives(e.g., Proxel, commercially available from Avecia), antifreeze agents(such as glycerol, sorbitol, or urea), and antifoam agents (such asAntifoam SE23 from Wacker Silicones Corp.).

Controlling Plant Growth with Microcapsule Dispersions

The microcapsule dispersions disclosed herein are useful ascontrolled-release herbicides or concentrates thereof. Therefore, thepresent invention is also directed to a method of applying a dispersionof the microencapsulated herbicides for controlling plant growth. Insome embodiments, herein, the dispersion of herbicidal microcapsules isapplied to the ground, over the tops of the crop plants (i.e., onto thefoliage), or a combination thereof.

A microcapsule dispersion may be applied to plants, e.g. crops in afield, according to practices known to those skilled in the art. Themicrocapsules are preferably applied as a controlled release deliverysystem for an agricultural chemical (e.g., acetanilide herbicide) orblend of agricultural chemicals contained therein. Because the meanrelease characteristics of a population of microcapsules of the presentinvention are adjustable, the timing of release initiation (or increaserelease) can be controlled thereby giving both commercially acceptableweed control and a commercially acceptable rate of crop injury.

When blended for end use on an agricultural field, the dispersion ofherbicide-containing microcapsules prior to dilution by the end user maybe, for example, less than about 62.5 weight percent microcapsules, oralternatively, less than about 55 weight percent herbicide or otheractive. If the dispersion is too concentrated with respect tomicrocapsules, the viscosity of the dispersion may be too high to pumpand also may be too high to easily redisperse if settling has occurredduring storage. It is for these reasons that the dispersion preferablyhas a viscosity of less than about 400 cps, as describe above.

The microcapsule dispersions may be as dilute with respect tomicrocapsule weight percent as is preferred by the user, constrainedmainly by the economics of storing and transporting the additional waterfor dilution and by possible adjustment of the additive package tomaintain a stable dispersion. Typically, the dispersion is at leastabout 25 weight percent herbicidal active (about 30 weight percentmicrocapsules) for these reasons. These concentrations are usefulcompositions for the storage and transport of the dispersions.

For a stand-alone (i.e., in the absence of a co-herbicide) applicationof the microcapsules of the present invention, the dispersion ispreferably diluted with water to form an application mixture prior toapplication to a field of crop plants. Typically, no additionaladditives are required to place the dispersion in a useful condition forapplication as a result of dilution. The optimal concentration of adiluted dispersion is dependent in part on the method and equipmentwhich is used to apply the herbicide.

The effective amount of microcapsules to be applied to an agriculturalfield is dependent upon the identity of the encapsulated herbicide, therelease rate of the microcapsules, the crop to be treated, andenvironmental conditions, especially soil type and moisture. Generally,application rates of herbicides, such as, for example, acetochlor, areon the order of about 1 kilogram of herbicide per hectare. But, theamount may vary by an order of magnitude or more in some instances,i.e., from 0.1 to 10 kilograms per hectare.

Application mixtures of the dispersions of the microencapsulatedacetamide herbicides are preferably applied to an agricultural fieldwithin a selected timeframe of crop plant development. In one embodimentof the present invention, the dispersion of the microencapsulatedherbicides is preferably applied to the crop plant after emergence(including cracking) and up to and including the six leaf stage andbefore emergence of the weeds.

Application mixtures of the aqueous dispersions of herbicidalmicrocapsules of the present invention are useful for controlling a widevariety of weeds, i.e., plants that are considered to be a nuisance or acompetitor of commercially important crop plants, such as corn, soybean,cotton, etc. In some embodiments, the microcapsules of the presentinvention are applied before the weeds emerge (i.e., pre-emergenceapplication). Examples of weeds that may be controlled according to themethod of the present invention include, but are not limited to, MeadowFoxtail (Alopecurus pratensis) and other weed species with theAlopecurus genus, Common Barnyard Grass (Echinochloa crus-galli) andother weed species within the Echinochloa genus, crabgrasses within thegenus Digitaria, White Clover (Trifolium repens), Lambsquarters(Chenopodium berlandieri), Redroot Pigweed (Amaranthus retroflexus) andother weed species within the Amaranthus genus, Common Purslane(Portulaca oleracea) and other weed species in the Portulaca genus,Chenopodium album and other Chenopodium spp., Setaria lutescens andother Setaria spp., Solanum nigrum and other Solanum spp., Loliummultiflorum and other Lolium spp., Brachiaria platyphylla and otherBrachiaria spp., Sorghum halepense and other Sorghum spp., ConyzaCanadensis and other Conyza spp., and Eleusine indica. In someembodiments, the weeds comprise one or more glyphosate resistantspecies, 2,4-D resistant species, dicamba resistant species and/or ALSinhibitor herbicide resistant species. In some embodiments, theglyphosate-resistant weed species is selected from the group consistingof Amaranthus palmeri, Amaranthus rudis, Ambrosia artemisiifolia,Ambrosia trifida, Conyza bonariensis, Conyza canadensis, Digitariainsularis, Echinochloa colona, Eleusine indica, Euphorbia heterophylla,Lolium multiflorum, Lolium rigidum, Plantago Ianceolata, Sorghumhalepense, and Urochloa panicoides.

As used herein transgenic glyphosate-tolerant corn, soybean, cotton,etc. plants includes plants grown from the seed of any corn, soybean,cotton, etc. event that provides glyphosate tolerance andglyphosate-tolerant progeny thereof.

Such glyphosate-tolerant events include, without limitation, those thatconfer glyphosate tolerance by the insertion or introduction, into thegenome of the plant, the capacity to express various native and variantplant or bacterial EPSPS enzymes by any genetic engineering means knownin the art for introducing transforming DNA segments into plants toconfer glyphosate resistance as well as glyphosate-tolerant cottonevents that confer glyphosate tolerance by other means such as describedin U.S. Pat. Nos. 5,463,175 and 6,448,476 and International PublicationNos. WO 2002/36782, WO 2003/092360 and WO 2005/012515.

Non-limiting examples of transgenic glyphosate-tolerant cotton eventsinclude the glyphosate-tolerant (ROUNDUP READY) cotton event designated1445 and described in U.S. Pat. No. 6,740,488. Of particular interest inthe practice of the present invention are methods for weed control in acrop of transgenic glyphosate-tolerant cotton plants in which glyphosateresistance is conferred in a manner that allows later stage applicationof glyphosate herbicides without incurring significantglyphosate-mediated reproductive injury. Non-limiting examples of suchtransgenic glyphosate-tolerant cotton plants include those grown fromthe seed of the glyphosate-tolerant (ROUNDUP READY) FLEX cotton event(designated MON 88913 and having representative seed deposited withAmerican Type Culture Collection (ATCC) with Accession No. PTA-4854) andsimilar glyphosate-tolerant cotton events and progeny thereof asdescribed in International Publication No. WO 2004/072235.Glyphosate-tolerant (ROUNDUP READY FLEX) cotton event MON 88913 andsimilar glyphosate-tolerant cotton events may be characterized in thatthe genome comprises one or more DNA molecules selected from the groupconsisting of SEQ ID NO:1, SEQ ID NO:2, SEQ ID NO:3, and SEQ ID NO:4; orthe genome in a DNA amplification method produces an amplicon comprisingSEQ ID NO:1 or SEQ ID NO:2; or the transgenic glyphosate-tolerant cottonplants comprise a glyphosate tolerant trait that is genetically linkedto a complement of a marker polynucleic acid, and the marker polynucleicacid molecule is homologous or complementary to a DNA molecule selectedfrom the group consisting of SEQ ID NO:1 and SEQ ID NO:2 as described inInternational Publication No. WO 2004/072235, the entire contents ofwhich are incorporated herein by reference. A sequence listingcontaining each of SEQ ID NOS: 1, 2, 3, and 4 as disclosed inInternational Publication No. WO 2004/072235 is contained herein. Thesesequences are listed as SEQ ID NOS: 1, 2, 3, and 4, respectively.

As noted above, the glyphosate-tolerant (ROUNDUP READY FLEX) cottonevent MON 88913 allows for over-the-top application of glyphosateherbicides at advanced stages of plant development without incurringsignificant glyphosate-mediated reproductive injury (e.g., asquantified, for example, by flower pollen shed and/or lint yield). Ascompared to the previous commercial glyphosate-tolerant (ROUNDUP READY)cotton event designated 1445, glyphosate-tolerant (ROUNDUP READY FLEX)cotton event MON 88913 is particularly advantageous in allowing foliarapplication of glyphosate herbicide for weed control at a developmentalage characterized by at least five leaf nodes present on a cotton plantof the crop. As used herein, a node having a leaf branch is referred toas a leaf node in accordance with the conventional node method used inassessing cotton plant developmental age. Furthermore, cotyledons areleaves originally contained in the seed and are not considered as plantleaves or nodes for purposes of determination of the stage of cottondevelopment. That is, as generally accepted by those skilled in the artand as used herein, the stem point of cotyledon attachment is referencedas Node 0. The fifth and subsequent leaf nodes are typically the firstreproductive (i.e., fruiting) branches and may develop a fruiting budand associated leaf. A leaf node having a reproductive branch may bereferred as a reproductive node. Cotton plants can develop as many asabout 25 leaf nodes, with nodes 5-25 potentially developing intoreproductive nodes. In practicing weed control in a crop of transgenicglyphosate-tolerant cotton grown from seed of glyphosate-tolerant(ROUNDUP READY FLEX) cotton event MON 88913 or similar cotton events andprogeny thereof, glyphosate herbicidal formulations can be appliedover-the-top of the crop at more advanced developmental agescharacterized, for example, by six, ten, twelve, fourteen or more leafnodes present on a cotton plant of the crop and up to and includinglayby without incurring significant glyphosate-mediated reproductiveinjury to the crop. Herbicidal glyphosate formulation may be appliedover-the-top of the cotton crop at various intervals of advanceddevelopment, characterized, for example, by six or more leaf nodes andno more than ten, twelve, fourteen, sixteen, eighteen, twenty ortwenty-five leaf nodes on a cotton plant of the crop.

In some embodiments as described previously, the herbicidalmicrocapsules of the present invention can be dispersed in combinationwith one or more co-herbicides in an aqueous concentrate or sprayapplication tank mix, such as a co-herbicide selected from acetyl CoAcarboxylase inhibitors (such as aryloxyphenoxypropionics),organophosphorus herbicides, auxins (e.g., synthetic auxins),photosystem II inhibitors (such as ureas and triazines), ALS inhibitors(such as sulfonyl ureas, triazolopyrimidines and imidazolinones),protoporphyrinogen oxidase inhibitors (such as diphenyl ethers, phenylpyrazoles, aryl triazones and oxadiazoles) and carotenoid biosynthesisinhibitors (such as isoxazolidinones, benzoylcyclohexanediones,benzoylpyrazoles), salts and esters thereof, and mixtures thereof.Application mixtures of the co-herbicide formulations can likewise beprepared. A weight ratio of acetamide to co-herbicide of from 10:1 to1:10 or from 5:1 to 1:5 is preferred.

Where an herbicide is referenced generically herein by name, unlessotherwise restricted, that herbicide includes all commercially availableforms known in the art such as salts, esters, free acids and free bases,as well as stereoisomers thereof. For example, where the herbicide name“glyphosate” is used, glyphosate acid, salts and esters are within thescope thereof.

Organophosphorus herbicides include, for example, glyphosate,glufosinate, glufosinate-P, salts and esters thereof, and mixturesthereof.

Acetyl CoA carboxylase inhibitors include, for example, alloxydim,butroxydim, clethodim, cycloxydim, pinoxaden, sethoxydim, tepraloxydimand tralkoxydim, salts and esters thereof, and mixtures thereof. Anothergroup of acetyl CoA carboxylase inhibitors include chlorazifop,clodinafop, clofop, cyhalofop, diclofop, diclofop-methyl, fenoxaprop,fenthiaprop, fluazifop, haloxyfop, isoxapyrifop, metamifop,propaquizafop, quizalofop and trifop, salts and esters thereof, andmixtures thereof. Acetyl CoA carboxylase inhibitors also includemixtures of one or more “dims” and one or more “fops”, salts and estersthereof.

Auxin herbicides include, for example, 2,4-D, 2,4-DB, dichloroprop,MCPA, MCPB, aminopyralid, clopyralid, fluroxypyr, triclopyr, diclopyr,mecoprop, dicamba, picloram and quinclorac, salts and esters thereof,and mixtures thereof.

Photosystem II inhibitors include, for example, ametryn, amicarbazone,atrazine, bentazon, bromacil, bromoxynil, chlorotoluron, cyanazine,desmedipham, desmetryn, dimefuron, diruon, fluometuron, hexazinone,ioxynil, isoproturon, linuron, metamitron, methibenzuron, metoxuron,metribuzin, monolinuron, phenmedipham, prometon, prometryn, propanil,pyrazon, pyridate, siduron, simazine, simetryn, tebuthiuron, terbacil,terbumeton, terbuthylazine and trietazine, salts and esters thereof, andmixtures thereof.

ALS inhibitors include, for example, amidosulfuron, azimsulfruon,bensulfuron-methyl, bispyribac-sodium, chlorimuron-ethyl, chlorsulfuron,cinosulfuron, cloransulam-methyl, cyclosulfamuron, diclosulam,ethametsulfuron-methyl, ethoxysulfuron, flazasulfuron, florazulam,flucarbazone, flucetosulfuron, flumetsulam, flupyrsulfuron-methyl,foramsulfuron, halosulfuron-methyl, imazamethabenz, imazamox, imazapic,imazapyr, imazaquin, imazethapyr, imazosulfuron, iodosulfuron,metsulfuron-methyl, nicosulfuron, penoxsulam, primisulfuron-methyl,propoxycarbazone-sodium, prosulfuron, pyrazosulfuron-ethyl,pyribenzoxim, pyrithiobac, rimsulfuron, sulfometuron-methyl,sulfosulfuron, thifensulfuron-methyl, triasulfuron, tribenuron-methyl,trifloxysulfuron and triflusulfuron-methyl, salts and esters thereof,and mixtures thereof.

Protoporphyrinogen oxidase inhibitors include, for example, acifluorfen,azafenidin, bifenox, butafenacil, carfentrazone-ethyl, flufenpyr-ethyl,flumiclorac, flumiclorac-pentyl, flumioxazin, fluoroglycofen,fluthiacet-methyl, fomesafen, lactofen, oxadiargyl, oxadiazon,oxyfluorfen, pyraflufen-ethyl and sulfentrazone, salts and estersthereof, and mixtures thereof.

Carotenoid biosynthesis inhibitors include, for example, aclonifen,amitrole, beflubutamid, benzofenap, clomazone, diflufenican, fluridone,flurochloridone, flurtamone, isoxaflutole, mesotrione, norflurazon,picolinafen, pyrazolynate, pyrazoxyfen, sulcotrione and topramezone,salts and esters thereof, and mixtures thereof.

In some embodiments the herbicidal microcapsules of the presentinvention can be dispersed with two co-herbicides to form a three-wayherbicidal composition. The compositions can be concentrate compositionsor application mixtures. A weight ratio of acetamide to totalco-herbicide of from 10:1 to 1:10 or from 5:1 to 1:5 is preferred. Insome embodiments, the encapsulated acetamides are combined in an aqueousapplication mixture with an auxin herbicide and an organophosphateherbicide, or salts or esters thereof. In some embodiments, theencapsulated acetamide herbicide is selected from acetochlor,metolachlor, S-metolachlor, dimethenamide and dimethenamide-P salts andesters thereof, the first co-herbicide is selected from dicamba and2,4-D, salts and esters thereof, and the second co-herbicide is selectedfrom glyphosate, glufosinate and glufosinate-P, salts and estersthereof. Examples include: encapsulated acetochlor, dicamba andglyphosate; encapsulated metolachlor and/or S-metolachlor, dicamba andglyphosate; encapsulated dimethenamid and/or dimethenamid-P, dicamba andglyphosate; encapsulated acetochlor, 2,4-D and glyphosate; encapsulatedmetolachlor and/or S-metolachlor, 2,4-D and glyphosate; encapsulateddimethenamid and/or dimethenamid-P, 2,4-D and glyphosate; encapsulatedacetochlor, dicamba and glufosinate and/or glufosinate-P; encapsulatedmetolachlor and/or S-metolachlor, dicamba and glufosinate and/orglufosinate-P; encapsulated dimethenamid and/or dimethenamid-P, dicambaand glufosinate and/or glufosinate-P; encapsulated acetochlor, 2,4-D andglufosinate and/or glufosinate-P; encapsulated metolachlor and/orS-metolachlor, 2,4-D and glufosinate and/or glufosinate-P; andencapsulated dimethenamid and/or dimethenamid-P, 2,4-D and glufosinateand/or glufosinate-P.

In a preferred embodiment, the present microcapsules are used in thepreparation of an aqueous concentrate composition or tank mix comprisingglyphosate or a salt thereof (e.g., the potassium or monoethanolammoniumsalt). In such a tank mix, a percent by weight acetamide from about 3%to about 0.25% a.e. and from about 3% by weight to about 0.25% a.e. byweight is preferred. Such an aqueous composition is particularly usefulfor use over glyphosate-tolerant crop plants to control glyphosatesusceptible plants and several commercially important weeds that havebeen reported to be glyphosate resistant, including, for example, palmeramaranth (Amaranthus palmeri), waterhemp (Amaranthus rudis), commonragweed (Ambrosia artemisiifolia), giant ragweed (Ambrosia trifida),hairy fleaane (Conyza bonariensis), horseweed (Conyza canadensis),sourgrass (Digitaria insularis), junglerice (Echinochloa colona),goosegrass (Eleusine indica), wild poinsettia (Euphorbia heterophylla),Italian ryegrass (Lolium multiflorum), rigid ryegrass (Lolium rigidum),buckhorm plantain (Plantago lanceolata), Johnsongrass (Sorghumhalepense), and liverseedgrass (Urochloa panicoides).

As used throughout this specification, the expression “predominantlycomprises” means more than 50%, preferably at least about 75%, and morepreferably at least about 90% by weight of the component is made up ofthe specified compound(s).

Having described the invention in detail, it will be apparent thatmodifications and variations are possible without departing from thescope of the invention defined in the appended claims.

EXAMPLES

The following non-limiting Examples are provided to further illustratethe present invention. In each of the Examples, the materials shown inthe following Table were used. Throughout the Examples, these componentsare referred to by the term stated in the Reference column.

Material Function Reference Supplier Acetochlor Herbicide AcetochlorMonsanto Furilazole Safener Monsanto n-Pentadecane Internal Phase NORPAR15 Exxon Mobil Solvent (dilutent) Isoparaffinic Internal Phase ISOPAR VExxon Mobil hydrocarbon Solvent (dilutent) (approximate MW 234)Isoparaffinic Internal Phase ISOPAR L Exxon Mobil hydrocarbon Solvent(dilutent) (approximate MW 163) Dearomatized Internal Phase EXXSOL D-130Exxon Mobil hydrocarbon Solvent (dilutent) (approximate MW 229)Dearomatized Internal Phase EXXSOL D-110 Exxon Mobil hydrocarbon Solvent(dilutent) (approximate MW 200) Triethylenetetramine Amine shell TETAHuntsman 50% solution wall component Chemical Meta-Xylylenediamine Amineshell XDA 50% solution wall component Desmodur N3200 Triisocyanate shellDES N3200 Bayer Trimer of wall component hexamethylene-1,6- diisocyanateDesmodur W Diisocyanate shell DES W Bayer 4,4′-diisocyanato- wallcomponent dicyclohexyl methane 85% by weight trimer of Blend of DESMISTAFLEX Monsanto hexamethylene-1,6- N3200 and DES W diisocyanate:15%by weight 4,4′-diisocyanato- dicyclohexyl methane Water External PhaseSolvent Water Ammonium Dispersant Ammonium American Casein caseinatecaseinate Company Glycerin Glycerin Cargill Maleic acid-olefinsurfactant SOKALAN CP9 BASF copolymer, 25% solution Citric Acid, pHadjustment Acid ADM 50% solution Invalon DAM Dispersant Invalon HuntsmanNaphthalene formaldehyde Chemical condensate sulfonate Kelzan CCThickener Kelzan CC Kelco Proxel GXL Preservative Proxel GXL AveciaNAOH, 20% solution pH adjustment Caustic Dow Chemical Antifoam SE23Antifoam Antifoam Wacker Silicone Na₂HPO₄ Buffer Buffer ICL PerformanceProducts

The herbicidal effectiveness data set forth herein report crop damageand weed inhibition as a phytotoxicity percentage following a standardprocedure in the art which reflects a visual assessment of plantmortality and growth reduction by comparison with untreated plants, madeby technicians specially trained to make and record such observations.In all cases, a single technician makes all assessments of percentinhibition within any one experiment or trial.

The selection of application rates that are biologically effective for aspecific acetamide herbicide is within the skill of the ordinaryagricultural scientist. Those of skill in the art will likewiserecognize that individual plant conditions, weather and growingconditions, as well as the specific exogenous chemical and formulationthereof selected, will affect the efficacy on weeds and associated cropinjury achieved in practicing this invention. Useful application ratesfor the acetamide herbicides employed can depend upon all of the abovefactors. With respect to the use of the method of this invention, muchinformation is known about appropriate acetamide application rates. Overfour decades of acetamide use and published studies relating to such usehave provided abundant information from which a weed controlpractitioner can select acetamide application rates that areherbicidally effective on particular species at particular growth stagesin particular environmental conditions.

Effectiveness in greenhouse tests, usually at exogenous chemical rateslower than those normally effective in the field, is a proven indicatorof consistency of field performance at normal use rates. However, eventhe most promising composition sometimes fails to exhibit enhancedperformance in individual greenhouse tests. As illustrated in theExamples herein, a pattern of enhancement emerges over a series ofgreenhouse tests; when such a pattern is identified this is strongevidence of biological enhancement that will be useful in the field.

The compositions of the present invention can be applied to plants byspraying, using any conventional means for spraying liquids, such asspray nozzles, atomizers, or the like. Compositions of the presentinvention can be used in precision farming techniques, in whichapparatus is employed to vary the amount of exogenous chemical appliedto different parts of a field, depending on variables such as theparticular plant species present, soil composition, and the like. In oneembodiment of such techniques, a global positioning system operated withthe spraying apparatus can be used to apply the desired amount of thecomposition to different parts of a field.

The composition, at the time of application to plants, is preferablydilute enough to be readily sprayed using standard agricultural sprayequipment. Preferred application rates for the present invention varydepending upon a number of factors, including the type and concentrationof active ingredient and the plant species involved. Selection ofappropriate rates of application is within the capability of one skilledin the art. Useful rates for applying an aqueous application mixture toa field of foliage can range from about 50 to about 1,000 liters perhectare (L/ha) by spray application. The preferred application rates foraqueous application mixtures are in the range from about 100 to about300 L/ha.

Damage to the foliage of a crop plant may cause the plant to be stuntedor otherwise reduce the yield of the desired agricultural commodity.Thus, it is important that a herbicidal composition not be applied insuch a manner as to excessively injure and interrupt the normalfunctioning of the plant tissue. However, some limited degree of localinjury can be insignificant and commercially acceptable.

A large number of compositions of the invention are illustrated in theexamples that follow. Many concentrate acetamide compositions haveprovided sufficient herbicidal effectiveness in greenhouse tests towarrant field testing on a wide variety of weed species under a varietyof application conditions.

The experiments were carried out in a greenhouse. The herbicidalcompositions were applied post-emergence to crops on or before the2-6-leaf stage using a research track sprayer. Test compositions wereapplied at a spray volume 94 L/ha applied by means compressed air at apressure of 165 kpa. The dilution of the dispersion of herbicidalmicrocapsules were varied in order achieve different concentrations ofactive applied. Weed control testing was accomplished by applying theherbicidal compositions to the soil prior to weed emergence. Three daysafter application, the samples were irrigated with 0.125 inches ofoverhead irrigation and sub-irrigated as needed throughout the study.

Example 1. Preparation of Aqueous Dispersions of MicroencapsulatedAcetochlor

Aqueous dispersions of microencapsulated acetochlor were preparedaccording to the protocol described in this example. The aqueousdispersions were prepared using a method that resulted in microcapsuleshaving a mean diameter greater than those found in DEGREE, acommercially available microencapsulated herbicidal product containingabout 42% by weight acetochlor, available from Monsanto Company. Themicrocapsules in DEGREE have a mean diameter of about 2.5 μm. The testformulations resulted in aqueous dispersions of microcapsules havingmean diameters significantly greater, such as about 5 μm to about 13 μm.Field studies indicated that the aqueous dispersions of herbicidalmicrocapsules having larger mean diameters exhibited improved cropsafety when tested on soybean and cotton compared to DEGREE and alsocompared to HARNESS, a commercially available herbicidal productcontaining emulsified concentrate of unencapsulated acetochlor, alsoavailable from Monsanto Company.

The internal phases were prepared to contain the components and amountsshown in the following table. The percentages indicate the approximateweight percentage of each component in the aqueous dispersion.

TABLE Internal Phase Components Acetochlor NORPAR 15 MISTAFLEX Form. (g)(%) (g) (%) (g) (%) 5291 447.25 43.19 23.56 2.35 30.84 3.07 5297 894.2143.19 46.99 2.35 61.53 3.07 5295 841.2 40.63 107.01 5.00 61.73 3.07

To prepare the internal phase of formulations 5291, 5297, and 5295,acetochlor was charged to the mixing vessels in the amounts shown in theabove internal phase components table. Next, NORPAR 15 was charged tothe mixing vessels, followed by the MISTAFLEX blend of DES N3200 and DESW polyisocyanates. The solution was agitated to obtain a clearhomogenous solution. The solution may be sealed within the mixing vesseland stored until needed. Prior to use, the mixture was heated to 50° C.in an oven.

The external aqueous phases were prepared containing the components andamounts shown in the following table:

TABLE External Phase Components Weight of Components in grams AmmoniumSOKALAN Form. Water Caseinate Glycerin CP9 Acid 5291 278.2 0.45 81.123.0 1.64 5297 556.61 0.98 162.28 46.04 3.09 5295 556.32 0.93 162.2746.63 3.23

To prepare the external phase of formulations 5291, 5297, and 5295,mixing vessels were charged with water in the amounts shown in the aboveexternal phase components table, and the remaining components were addedin the order shown in the above table. The solution was agitated toobtain a clear homogenous solution. The solution may be sealed withinthe mixing vessel and stored until needed. Prior to use, the mixture washeated to 50° C. in an oven.

The interfacial polymerization medium was prepared by first charging theexternal phase to a Waring blender cup that has been preheated to 50° C.The commercial Waring blender (Waring Products Division, DynamicsCorporation of America, New Hartford, Conn., Blender 700) was poweredthrough a 0 to 120 volt variable autotransformer. The blender mix speedwas varied by controlling power to the blender as shown below in theemulsification parameters table. The internal phase was added to theexternal phase over a 16 second interval and blending was continued toobtain an emulsion.

TABLE Emulsification Parameters Form. Voltage (V) Power (%) Duration (s)5297 120 40 120 5295 120 40 —

To initiate polymerization and encapsulation of the internal phase, a50% by weight solution of TETA was added to the emulsion to the amountsshown in the following Amine Table over a period of about 5 seconds. Theblender speed is then reduced to a speed which just produces a vortexfor approximately five to fifteen minutes. The emulsion was thentransferred to a hot plate and stirred. The reaction vessel is coveredand maintained at about 50° C. for approximately two hours which hasbeen found is sufficient time for the isocyanate to react essentiallycompletely.

TABLE Amine TETA, 50% by weight solution Form. (g) (%) 5291 14.14 1.39%5297 27.72 1.39% 5295 27.92 1.39%

The capsule slurry is then allowed to cool to close to room temperature.The components shown in the stabilizer components table with theexception of the buffer are previously premixed with a high speed mixer(Waring Blender or Cowles Dissolver). The resulting stabilizer premix isthen added to the capsule slurry to stabilize the dispersion ofmicrocapsules. Finally the buffer is added and the mixture is stirredfor at least 15 minutes until visually homogeneous.

Due to variations in the blender design and other uncontrollablevariables, it was found to be difficult to correlate blender speed andparticle size accurately. In consequence, some samples were discardedbecause they did not have the desired size. Samples were chosen forevaluation based on their measured particle size.

TABLE Stabilizer Components Weight of Components in grams Form. InvalonGlycerin Kelzan CC 5291 58.41 39.2 0.53 5297 116.83 78.37 1.04 5295116.83 78.37 1.04 Form. Proxel GXL Caustic Antifoam Buffer 5291 0.530.23 0.01 1.18 5297 1.04 0.354 0.01 2.38 5295 1.04 0.354 0.01 2.38

Formulations 5291, 5297, and 5295 were stabilized aqueous dispersions ofmicrocapsules containing acetochlor at an approximate activeconcentration of 42.5% AI by weight (which approximately the same activeconcentration as DEGREE).

Each formulation was prepared to have an excess molar equivalents ratiosof amine molar equivalents to isocyanate molar equivalents and herbicideto shell wall component ratios. TETA has an approximate equivalentweight of 36.6 g/mol. DES N3200 has an approximate equivalent weight of183 g/mol (theoretical equivalent weight is 159.53 g/mol). DES W has anapproximate equivalent weight of 132 g/mol. Formulation 5295 wasprepared with an excess of internal phase solvent (diluent), NORPAR 15.The formulations had the following weight ratios:

TABLE Formulation Characteristics Ratio of Ratio of Molar HerbicideHerbicide equivalents to Shell Wall to Internal Form. ratio ComponentsPhase Solvent 5291 1.08:1 9.94:1 18.98:1 5297 1.06:1 10.02:1  19.03:15295 1.06:1 9.38:1  7.86:1

The blender speed was controlled to produce an increased microcapsulesize compared to the microcapsules in DEGREE, which is about 2.5 μm. Themean particle sizes and standard deviations of the microcapsules in theslurry for each formulation are shown in the following table:

TABLE Particle Size Parameters Form. Mean Particle size (μm) StandardDeviation (μm) 5291 5.57 3.99 5297 13.97 8.5 5295 12.70 7.85The particle size parameters were measured using a Beckman Coulter LSParticle Size Analyzer.

Example 2. Study of Soybean and Cotton Crop Safety and Post-EmergenceWeed Control Efficacy Using Microencapsulated Acetochlor Formulations ofthe Invention

Formulations 5291, 5297, and 5295 (prepared according to the methoddescribed above in Example 1) were applied to glyphosate-tolerant(ROUNDUP READY) soybean and dicamba-tolerant soybeans andglyphosate-tolerant (ROUNDUP READY) cotton (RR Flex—short to mid-seasonvariety) crops under greenhouse conditions. These formulations weretested against commercial acetochlor formulations HARNESS and DEGREE.The formulations were applied to post-emergent soybean and cotton plantsand measured for phytotoxicity at 7, 8, and 9 days after treatment(“DAT”). The results are shown in FIG. 1 (Cotton injury 7 DAT), FIG. 2(Soybean injury at 8 DAT), FIG. 3 (Soybean injury at 9 DAT), and FIG. 4(Soybean injury at 9 DAT).

All three experimental formulations provided significantly better cropsafety in glyphosate-tolerant (ROUNDUP READY) cotton than DEGREE at thetwo highest acetochlor application rates (See FIG. 1). Additionally, allencapsulated formulations showed substantially better crop safety thanHARNESS at all three application rates. A similar relationship wasobserved in glyphosate-tolerant (ROUNDUP READY) soybeans; however, inthis case the three experimental formulations exhibited significantlybetter crop safety than DEGREE at all application rates (SEE FIG. 2).Again, all encapsulated formulations provided significantly better cropsafety than HARNESS. Crop injury in dicamba-tolerant (DMO) soybeans wassimilar to that seen in glyphosate-tolerant (ROUNDUP READY) soybeanswith no significant differences observed between the two events (SeeFIGS. 3 and 4). “DMO” refers to a plant expressing a dicambamonooxygenase (DMO) gene that functions to degrade dicamba therebyconferring dicamba tolerance. Crop injury was less overall anddifferences between the various encapsulated formulations were lesspronounced in the dicamba-tolerant soybean study than that seen inglyphosate-tolerant (ROUNDUP READY) soybeans; however, these were twoseparate studies so comparing across studies is not entirely valid. Onecould conclude though that dicamba-tolerant soybeans toleratepost-emergent (“POE”) applications of acetochlor formulations similar toglyphosate-tolerant (ROUNDUP READY) soybeans.

These data suggest that these experimental formulations provide improvedpost-emergence crop safety over both DEGREE and HARNESS relative toglyphosate-tolerant (ROUNDUP READY) cotton, glyphosate-tolerant (ROUNDUPREADY) soybeans, and dicamba-tolerant soybeans.

Formulations 5291, 5297, and 5295, prepared according to the methoddescribed in Example 1, were also tested for preemergence applicationweed control efficacy and compared to the weed control efficacy of bothDEGREE and HARNESS. The weed species tested included Redroot pigweed(Amaranthus retroflexus), Lambsquarters (Chenopodium album), Yellowfoxtail (Setaria lutescens), and Barnyardgrass (Echinochloa crus-galli).

Substantially greater weed control was evident with all encapsulatedformulations in this study. Formulations 5291 and 5297 provided efficacythat was equivalent or superior to that found with DEGREE. See FIGS. 5through 8. Formulation 5295 (having a greater proportion of internalphase solvent compared to formulations 5291 and 5297) showedsignificantly less control than all other formulations versus all fourspecies at most application rates. This suggests that excess internalphase solvent may inhibit release of acetochlor to such an extent thatweed control efficacy may be compromised.

Example 3. Preparation of Aqueous Dispersions of MicroencapsulatedAcetochlor

Three aqueous dispersions of microencapsulated acetochlor (designatedformulations 3993, 3995, and 3997) were prepared. All formulations wereprepared using the same amine (TETA) and isocyanate (DES N3200), and allformulations contained internal phase solvent, NORPAR 15. The relativeratios of components were held approximately constant. Theseformulations were prepared using an excess of amine equivalents. Theratios of amine molar equivalents to isocyanate molar equivalents were1.29:1, 1.26:1, and 1.25:1 in formulations 3993, 3995, and 3997respectively. The mean particle sizes of each the various formulationswere controlled by varying the mixing speed during emulsification.

Formulations 3993, 3995, and 3997 contained the components shown in thefollowing table:

Form. 3993 Form. 3995 Form. 3997 Component Weight of Component (g)Internal Phase Acetochlor 175.0 175.0 175 NORPAR 15 9.3 9.3 9.11 DESN3200 13.01 12.87 12.79 External Phase Glycerin 32.5 32.0 32.0 SOKALANCP9 9.45 9.48 9.41 Ammonium Caseinate 0.19 0.19 0.19 Acid 0.72 0.75 0.72Water 115.0 115.0 115.0 TETA, 50% solution 6.71 6.5 6.4 StabilizerInvalon 23.65 23.65 23.65 Kelzan CC 0.21 0.21 0.21 Antifoam 0 0 0Glycerin 15.85 15.85 15.85 Proxel GXL 0.21 0.21 0.21 Caustic 0.07 0.070.07 Buffer 0.47 0.47 0.47

The aqueous dispersions of microcapsules were prepared substantially asdescribed above in Example 1. During emulsification, the mixer speed wasvaried by controlling the blender to achieve mean particle sizes asshown in the table:

TABLE Particle Size Parameters Formulation Mean Particle size (μm)Standard Deviation (μm) 3993 2.01 1.14 3995 9.49 6.31 3997 10.80 7.9

Example 4. Preparation of Aqueous Dispersions of MicroencapsulatedAcetochlor

Three aqueous dispersions of microencapsulated acetochlor (designatedformulations 2805A, 2805B, and 2805C) were prepared. These formulationswere prepared using MISTAFLEX polyisocyanate blend. These formulationswere additionally prepared without the internal phase solvent, NORPAR15. The ratio of amine molar equivalents to isocyanate molar equivalentswas approximately 1.03:1 to 1.04 for each formulation. The mean particlesizes of each the various formulations were controlled varying themixing speed during emulsification.

To prepare these formulations, large batches of each of the internalphase, the external phase, and the stabilizer solution were preparedcontaining the components and amounts shown in the following table.

Form. 2805A Form. 2805B Form. 2805C Component Weight of Component (g)Internal Phase Acetochlor 530 DES N3200 31.99 DES W 5.65 External PhaseGlycerin 104.0 SOKALAN CP9 30.6 Ammonium Caseinate 0.60 Acid 2.22 Water373.0 TETA, 50% solution 5.48 5.50 5.39 Stabilizer Invalon 71.83Glycerin 48.15 Kelzan CC 0.64 Proxel GXL 0.64 Caustic 0.22 Antifoam 0.01Buffer 1.43

The aqueous dispersions of microcapsules were prepared substantially asdescribed above in Example 1. To prepare each formulation, the internalphase, external phase, and stabilizer batches were divided into smallerapproximately equal weight batches and combined as described inExample 1. Three separate amine solutions were used to initiatepolymerization. During emulsification, the mixer speed was varied bycontrolling the blender to achieve mean particle sizes as shown in thetable:

TABLE Particle Size Parameters Formulation Mean Particle size (μm)Standard Deviation (μm) 2805A 2.26 1.27 2805B 9.73 6.33 2805C 15.8912.51

Example 5. Study of Soybean and Cotton Crop Safety UsingMicroencapsulated Acetochlor Formulations of the Invention

Formulations 3993, 3995, 3997, 2805A, 2805B, and 2805C were applied toglyphosate-tolerant (ROUNDUP READY) soybean (variety AG 4403) andglyphosate-tolerant (ROUNDUP READY) cotton (RR Flex—short to mid-seasonvariety) crops under greenhouse conditions. These formulations weretested against HARNESS and DEGREE. The formulations were applied topost-emergent soybean and cotton plants and measured for phytotoxicity14 DAT. The results are shown in FIG. 9 (Cotton injury) and FIG. 10(Soybean injury).

Formulations 3993, 3995, 3997, and 2805C all provided better crop safetyin glyphosate-tolerant (ROUNDUP READY) cotton than DEGREE at the highestrate tested and at least one of the two lower rates (FIG. 9).Formulations 2805A and 2805B were not significantly different fromDegree at the two higher application rates. Results inglyphosate-tolerant (ROUNDUP READY) soybeans showed all experimentalformulations to be less injurious than DEGREE at the highest applicationrate (FIG. 10). However, only Formulations 3993, 3995, and 3997 providedbetter crop safety at the middle application rate. The release rates forthe tested formulations was measured according to the above describedprotocol wherein a dispersion of 1% by weight of the encapsulatedacetochlor in deionized water was agitated at 150 RPM and 25° C. in aSOTAX AT-7 agitated dissolution test apparatus and sampled at 6 hoursand 24 hours. The release rates of the tested formulations is reportedin the following table.

Formulation Release at 6 hours (ppm) Release at 24 hours (ppm) 3993 211280 3995 80 104 3997 96 128 2805A 179 312 2805B 91 152 2805C 88 140DEGREE 129 200 DEGREE 123 200

Example 6. Weed Control Efficacy Using Microencapsulated AcetochlorFormulations of the Invention

Formulations 3993, 3995, 3997, 2805A, 2805B, and 2805C, preparedaccording to the methods described in Examples 3 and 4, were tested forweed control efficacy and compared to the weed control efficacy of bothDEGREE and HARNESS. The weed species tested included Redroot pigweed(Amaranthus retroflexus), Lambsquarters (Chenopodium album), Yellowfoxtail (Setaria lutescens), and Barnyardgrass (Echinochloa crus-galli).The weed control efficacy data are presented in FIGS. 11 through 18.

Relatively high levels of weed control were also evident in this study.See FIGS. 11 through 14. The data suggest some weakness withFormulations 3995 and 3997 (large microcapsules prepared with a largeexcess of amine), while the remaining formulations look to be equivalentto DEGREE.

A follow-up study was then conducted with another modification to theprotocol. Application rates were lowered and watering was delayed foronly three days. The abbreviated delay in watering was instituted withthe hope of shortening the length of the assay, while maintaining goodefficacy for separating formulations. Data from this study confirmed theweaker efficacy of Formulations 3995 and 3997, particularly as itrelates to redroot pigweed and barnyardgrass control. See FIGS. 15through 18. These data also show lower efficacy with Formulation 2805C(particles having mean diameter of 15.89 μm). The three remainingexperimental formulations, 3993, 2805A, and 2805B all showed efficacywhich was equivalent to or better than that of DEGREE.

Example 7. Preparation of Aqueous Dispersions of MicroencapsulatedAcetochlor

Three aqueous dispersions of microencapsulated acetochlor (designatedformulations 831A, 831B, and 831D) were prepared. These formulationswere prepared using a blend of amines, TETA and XDA, in an approximateweight % ratio of 70:30 and the MISTAFLEX blend of polyisocyanatescomprising DES N3200 and DES W. The ratio of amine molar equivalents toisocyanate molar equivalents was approximately 1.04:1 to 1.05:1 for eachof these formulations. The mean particle sizes of each the variousformulations were controlled varying the mixing speed duringemulsification.

To prepare these formulations, large batches of each of the internalphase, the external phase, the amine solution, and the stabilizersolution were prepared containing the components and amounts shown inthe following table:

Form. 831A Form. 831B Form. 831D Component Weight of Component (g)Internal Phase Acetochlor 504.01 NORPAR 15 26.27 MISTAFLEX H9915 36.60External Phase Glycerin 103.05 SOKALAN CP9 30.38 Ammonium Caseinate 0.61Acid 2.35 Water 372.01 TETA, 50% solution 4.35 4.38 4.37Xylylenediamine, 1.90 1.91 1.87 50% solution Stabilizer Invalon 71.83Glycerin 0.64 Kelzan CC 0.01 Proxel GXL 48.15 Caustic 0.64 Antifoam 0.22Buffer 1.43

The aqueous dispersions of microcapsules were prepared substantially asdescribed above in Example 1. To prepare each formulation, the internalphase, external phase, and stabilizer batches were divided into smallerapproximately equal weight batches and combined as described inExample 1. Three separate amine solutions were used to initiatepolymerization. During emulsification, the mixer speed was varied bycontrolling the blender to achieve mean particle sizes as shown in thetable:

TABLE Particle Size Parameters Formulation Mean Particle size (μm)Standard Deviation (μm) 831A 2.11 1.22 831B 8.48 5.82 831D 11.7

Example 8. Preparation of Aqueous Dispersions of MicroencapsulatedAcetochlor

Four aqueous dispersions of microencapsulated acetochlor (designatedformulations 838A, 838B, 838C, and 838D) were prepared. Theseformulations were prepared using a blend of amines, TETA and XDA,similarly to Example 7, but the weight % ratio was changed to 80:20. Theformulations were prepared using the MISTAFLEX blend of polyisocyanatescomprising DES N3200 and DES W. The ratio of amine molar equivalents toisocyanate molar equivalents was approximately 1.04:1 to 1.05:1 for eachof these formulations. The mean particle sizes of each the variousformulations were controlled varying the mixing speed duringemulsification.

To prepare these formulations, large batches of each of the internalphase, the external phase, the amine solution, and the stabilizersolution were prepared containing the components and amounts shown inthe following table:

Form. 838A Form. 838B Form. 838C Form. 838D Component Weight ofComponent (g) Internal Phase Acetochlor 669.0 NORPAR 15 34.92 MISTAFLEX49.10 H9915 External Phase Glycerin 137.0 SOKALAN 40.45 CP9 Ammonium0.81 Caseinate Acid 3.10 Water 494.00 TETA, 50% 4.80 4.79 4.78 4.80solution Xylylene- 1.2 1.21 1.22 1.21 diamine, 50% solution StabilizerInvalon 95.48 Glycerin 0.86 Kelzan CC 0.02 Proxel GXL 64.0 Caustic 0.86Antifoam 0.29 Buffer 1.91

The aqueous dispersions of microcapsules were prepared substantially asdescribed above in Example 1. To prepare each formulation, the internalphase, external phase, and stabilizer batches were divided into smallerapproximately equal weight batches and combined as described inExample 1. Four separate amine solutions were used to initiatepolymerization. During emulsification, the mixer speed was varied bycontrolling the blender to achieve mean particle sizes as shown in thetable:

TABLE Particle Size Parameters Formulation Mean Particle size (μm)Standard Deviation (μm) 838A 2.06 1.12 838B 6.74 4.44 838C 12.84 8.16838D 8.35 5.49

Example 9. Preparation of Aqueous Dispersions of MicroencapsulatedAcetochlor

Four aqueous dispersions of microencapsulated acetochlor (designatedformulations 843A, 843B, 843C, and 843D) were prepared. Theseformulations were prepared using a blend of amines, TETA and XDA,similarly to Examples 7 and 8, but the weight % ratio was changed to90:10. The formulations were prepared using the MISTAFLEX blend ofpolyisocyanates comprising DES N3200 and DES W. The ratio of amine molarequivalents to isocyanate molar equivalents was approximately 1.04:1 to1.05:1 for each of these formulations. The mean particle sizes of eachthe various formulations were controlled varying the mixing speed duringemulsification.

To prepare these formulations, large batches of each of the internalphase, the external phase, the amine solution, and the stabilizersolution were prepared containing the components and amounts shown inthe following table:

Form. 838A Form. 838B Form. 838C Form. 838D Component Weight ofComponent (g) Internal Phase Acetochlor 669.0 NORPAR 15 35.0 MISTAFLEX49.58 H9915 External Phase Glycerin 137.10 SOKALAN 40.40 CP9 Ammonium0.81 Caseinate Acid 3.0 Water 494.02 TETA, 50% 5.17 5.18 5.16 5.17solution Xylylene- 0.59 0.60 0.58 0.59 diamine, 50% solution StabilizerInvalon 95.48 Glycerin 0.86 Kelzan CC 0.02 Proxel GXL 64.0 Caustic 0.86Antifoam 0.29 Buffer 1.91

The aqueous dispersions of microcapsules were prepared substantially asdescribed above in Example 1. To prepare each formulation, the internalphase, external phase, and stabilizer batches were divided into smallerapproximately equal weight batches and combined as described inExample 1. Four separate amine solutions were used to initiatepolymerization. During emulsification, the mixer speed was varied bycontrolling the blender to achieve mean particle sizes as shown in thetable:

TABLE Particle Size Parameters Formulation Mean Particle size (μm)Standard Deviation (μm) 843A 2.18 1.16 843B 7.62 5.05 843C 11.68 7.92843D 5.58 3.74

Example 10. Study of Soybean and Cotton Crop Safety and Post-EmergenceWeed Control Efficacy Using Microencapsulated Acetochlor Formulations ofthe Invention

Formulations 831A, 831B, 831D, 838A, 838D, 838C, 843A, 843B, and 843C(prepared according to the methods described in Examples 7, 8, and 9)were applied to glyphosate-tolerant (ROUNDUP READY) soybean (AG 4403)and glyphosate-tolerant (ROUNDUP READY) cotton (RR Flex—short tomid-season variety) crops under greenhouse conditions. Theseformulations were tested against commercial formulations HARNESS andDEGREE. The formulations were applied to post-emergent soybean andcotton plants and measured for phytotoxicity 22 DAT. The results areshown in FIG. 19 (Cotton injury) and FIG. 20 (Soybean injury).

All formulations with small capsule size (831A, 838A, 843A) showedcotton and soybean injury that was essentially equivalent to that seenwith DEGREE. See FIGS. 19 and 20. Formulations 831A, 838A, and 843A werecharacterized by relatively high release rates, as measured in a SOTAXAT-7 dissolution test apparatus according to the method describedherein, while the other formulations released at somewhat slower rates.For comparison, the release from DEGREE was measured twice. See thefollowing table for the release rates of the tested formulations.

Formulation Release at 6 hours (ppm) Release at 24 hours (ppm) 831A 245305 831B 168 191 831D 156 182 838A 186 275 838D 170 214 838C 73 90 843A188 286 843B 94 123 843C 96 134 DEGREE 131 202 DEGREE 136 200

Formulations 831A, 831B, 831D, 838A, 838D, 838C, 843A, 843B, and 843Cwere also tested for weed control efficacy and compared to the weedcontrol efficacy of both DEGREE and HARNESS. The weed species testedincluded Redroot pigweed (Amaranthus retroflexus), Barnyardgrass(Echinochloa crus-galli), and Yellow foxtail (Setaria lutescens). Theweed control efficacy data are presented in FIGS. 21, 22, and 23.

As expected these formulations provided weed control efficacy versusredroot pigweed, barnyardgrass, and yellow foxtail on par with DEGREE.See FIGS. 21, 22, and 23). Formulations with the largest capsule sizes,831D, 838C, and 843C), however, provided weed control that was in mostcases inferior to DEGREE. Formulations with mid-size capsule showed thebest balance between improved crop safety and acceptable weed control.Changing the amine ratios (TETA:XDA) did not appear to influence cropsafety. There did appear to be a trend towards better weed controlefficacy with higher levels of TETA (see redroot pigweed andbarnyardgrass control).

Example 11. Preparation of Aqueous Dispersions of MicroencapsulatedAcetochlor

Two aqueous dispersions of microencapsulated acetochlor (designatedformulations 874A and 874B) were prepared. These formulations wereprepared using the MISTAFLEX blend of polyisocyanates comprising DESN3200 and DES W and a single amine, TETA. The ratio of amine molarequivalents to isocyanate molar equivalents was approximately 1.2:1 forthese formulations. The mean particle sizes of each the variousformulations were controlled varying the mixing speed duringemulsification.

To prepare these formulations, large batches of each of the internalphase, the external phase, the amine solution, and the stabilizersolution were prepared containing the components and amounts shown inthe following table:

Form. 874A Form. 874B Component Weight of Component (g) Internal PhaseAcetochlor 352.70 NORPAR 15 18.43 MISTAFLEX H9915 25.73 External PhaseGlycerin 64.60 SOKALAN CP9 19.06 Ammonium Caseinate 0.38 Acid 1.39 Water232.80 TETA, 50% solution 6.46 6.45 Stabilizer Invalon 47.89 Glycerin0.43 Kelzan CC 0.01 Proxel GXL 32.10 Caustic 0.43 Antifoam 0.15 Buffer0.96

The aqueous dispersions of microcapsules were prepared substantially asdescribed above in Example 1. To prepare each formulation, the largeinternal phase, external phase, and stabilizer batches were divided intosmaller approximately equal weight batches and combined as described inExample 1. Two separate amine solutions were used to initiatepolymerization. During emulsification, the mixer speed was varied bycontrolling the blender to achieve mean particle sizes as shown in thetable:

TABLE Particle Size Parameters Formulation Mean Particle size (μm)Standard Deviation (μm) 874A 2.02 1.06 874B 7.33 7.93

Example 12. Preparation of Aqueous Dispersions of MicroencapsulatedAcetochlor

Two aqueous dispersions of microencapsulated acetochlor (designatedformulations 877A and 877B) were prepared. These formulations wereprepared using the MISTAFLEX blend of polyisocyanates comprising DESN3200 and DES W and a single amine, TETA. The ratio of amine molarequivalents to isocyanate molar equivalents was slightly lower than inpreceding Example 11. Herein, the ratio is approximately 1.1:1 for theseformulations. The mean particle sizes of each the various formulationswere controlled varying the mixing speed during emulsification.

To prepare these formulations, large batches of each of the internalphase, the external phase, the amine solution, and the stabilizersolution were prepared containing the components and amounts shown inthe following table:

Form. 877A Form. 877B Component Weight of Component (g) Internal PhaseAcetochlor 353.0 NORPAR 15 18.43 MISTAFLEX H9915 26.30 External PhaseGlycerin 64.69 SOKALAN CP9 19.1 Ammonium Caseinate 0.38 Acid 1.40 Water233.08 TETA, 50% solution 6.02 6.02 Stabilizer Invalon 47.89 Glycerin0.43 Kelzan CC 0.01 Proxel GXL 32.10 Caustic 0.43 Antifoam 0.15 Buffer0.96

The aqueous dispersions of microcapsules were prepared substantially asdescribed above in Example 1. To prepare each formulation, the largeinternal phase, external phase, and stabilizer batches were divided intosmaller approximately equal weight batches and combined as described inExample 1. Two separate amine solutions were used to initiatepolymerization. During emulsification, the mixer speed was varied bycontrolling the blender to achieve mean particle sizes as shown in thetable:

TABLE Particle Size Parameters Formulations Mean Particle size (μm)Standard Deviation (μm) 877A 2.08 1.13 877B 7.68 5.14

Example 13. Preparation of Aqueous Dispersions of MicroencapsulatedAcetochlor

Two aqueous dispersions of microencapsulated acetochlor (designatedformulations 880A and 880B) were prepared. These formulations wereprepared using the MISTAFLEX blend of polyisocyanates comprising DESN3200 and DES W and a single amine, TETA. The ratio of amine molarequivalents to isocyanate molar equivalents was higher than in Example11. Herein, the ratio is approximately 1.3:1 for these formulations. Themean particle sizes of each the various formulations were controlledvarying the mixing speed during emulsification.

To prepare these formulations, large batches of each of the internalphase, the external phase, the amine solution, and the stabilizersolution were prepared containing the components and amounts shown inthe following table:

Form. 880A Form. 880B Component Weight of Component (g) Internal PhaseAcetochlor 353 NORPAR 15 18.42 MISTAFLEX H9915 25.33 External PhaseGlycerin 64.50 SOKALAN CP9 19.05 Ammonium Caseinate 0.37 Acid 1.40 Water232.5 TETA, 50% solution 6.88 6.87 Stabilizer Invalon 47.89 Glycerin0.43 Kelzan CC 0.01 Proxel GXL 32.10 Caustic 0.43 Antifoam 0.15 Buffer0.96

The aqueous dispersions of microcapsules were prepared substantially asdescribed above in Example 1. To prepare each formulation, the largeinternal phase, external phase, and stabilizer batches were divided intosmaller approximately equal weight batches and combined as described inExample 1. Two separate amine solutions were used to initiatepolymerization. During emulsification, the mixer speed was varied bycontrolling the blender to achieve mean particle sizes as shown in thetable:

TABLE Particle Size Parameters Formulations Mean Particle size (μm)Standard Deviation (μm) 880A 2.17 1.15 880B 8.21 5.20

Example 14. Preparation of Aqueous Dispersions of MicroencapsulatedAcetochlor

Two aqueous dispersions of microencapsulated acetochlor (designatedformulations 883A and 885A) were prepared. These formulations wereprepared using the MISTAFLEX blend of polyisocyanates comprising DESN3200 and DES W and a single amine, TETA. The ratio of amine molarequivalents to isocyanate molar equivalents was 1.15:1 and 1.25:1 forformulations 883A and 885A, respectively. The mean particle sizes ofeach the various formulations were controlled varying the mixing speedduring emulsification.

To prepare these formulations, the internal phase, the external phase,the amine solution, and the stabilizer solution were prepared containingthe components and amounts shown in the following table:

883A 885A Weight of Weight of Component Component (g) Component (g)Internal Phase Acetochlor 352.75 174.18 NORPAR 18.44 9.10 MISTAFLEX25.97 12.65 External Phase Glycerin 64.65 32.0 SOKALAN CP9 19.07 9.4Ammonium Caseinate 0.38 0.19 Acid 1.37 0.70 Water 232.92 115.0 TETA, 50%solution 12.63 6.67 Stabilizer Invalon 47.89 23.65 Kelzan CC 0.43 0.21Antifoam 0.01 0 Glycerin 32.10 15.85 Proxel GXL 0.43 0.21 Caustic 0.150.07 Buffer 0.96 0.47

The aqueous dispersions of microcapsules were prepared substantially asdescribed above in Example 1. During emulsification, the mixer speed wasvaried by controlling the blender to achieve mean particle sizes asshown in the table:

TABLE Particle Size Parameters Formulations Mean Particle size (μm)Standard Deviation (μm) 883A 2.27 2.28 885A 1.94 1.06

Example 15. Study of Soybean and Cotton Crop Safety and Post-EmergenceWeed Control Efficacy Using Microencapsulated Acetochlor Formulations ofthe Invention

Formulations 874A, 874B, 877A, 877B, 880A, 880B, 883A, and 885A(prepared according to the methods described in Examples 11 through 14)were applied to glyphosate-tolerant (ROUNDUP READY) soybean (AG 4403)and glyphosate-tolerant (ROUONDUP READY) cotton (RR Flex—short tomid-season variety) crops under greenhouse conditions. Theseformulations were tested against commercial formulations HARNESS andDEGREE and against Dual II MAGNUM, available from Syngenta, whichcomprises s-metalochlor as the active ingredient and proprietaryingredients. The formulations were applied to post-emergent soybean andcotton plants and measured for phytotoxicity. The results are shown inFIG. 24 (Soybean injury 15 DAT) and FIG. 25 (Cotton injury 20 DAT). Themost consistent crop safety was obtained with formulation 874B, 877B,and 800B. See FIGS. 24 and 25. All three formulations provided cropsafety that was significantly better than that seen with DEGREE orHARNESS. Note that each of these formulations had particles sizes in the7-8 micron range and that altering the amine levels did not appreciablychange results among the formulations. Dual II MAGNUM gave injury thatwas similar to these three in cotton, but showed significantly greaterinjury in soybeans. All remaining experimental formulations exhibitedcrop injury that was similar to or slightly less than that shown byDEGREE.

Formulations 874A, 874B, 877A, 877B, 880A, 880B, 883A, and 885A werealso tested for weed control efficacy and compared to the weed controlefficacy of both DEGREE and HARNESS. The weed species tested includedRedroot pigweed (Amaranthus retroflexus), Lambsquarters (Chenopodiumalbum), Barnyardgrass (Echinochloa crus-galli), and Yellow foxtail(Setaria lutescens). The weed control efficacy data are presented inFIGS. 26 through 29.

Overall these experimental formulations provided efficacy that wasgenerally equal to or better than that of DEGREE. See FIGS. 26 through29. Control of redroot pigweed showed that formulation 877B was lessefficacious at the lowest application, formulation 877A was lesseffective at the highest rate, and formulations 885A, 883A, 880A, 874A,and 874B showed better efficacy than both DEGREE and Dual II MAGNUM.Lambsquarter control indicated formulations 874A and 880B to be slightlyweaker than DEGREE. All other formulations were equal to or better thanDEGREE and Dual II MAGNUM. Yellow foxtail control was excellent with allformulations, although formulation 874B did show some weakness at thelowest application rate. All formulations were equal to or better thanDEGREE in the control of barnyardgrass. Note the significant weakness ofDual II MAGNUM in the control of barnyardgrass relative to all of theacetochlor formulations.

Example 16. Preparation of Aqueous Dispersions of MicroencapsulatedAcetochlor

Two aqueous dispersions of microencapsulated acetochlor (designatedformulations 911A and 911B) were prepared. These formulations wereprepared using a polyisocyanate blend of DES N3200 and DES W in anapproximately 50:50 weight ratio. The polyisocyanates and TETA amineused to prepare the shell wall were added to yield a ratio of aminemolar equivalents to isocyanate molar equivalents of approximately1.2:1. The mean particle sizes of each the various formulations werecontrolled varying the mixing speed during emulsification.

To prepare these formulations, large batches of each of the internalphase, the external phase, the amine solution, and the stabilizersolution were prepared containing the components and amounts shown inthe following table:

Form 911A Form. 911B Component Weight of Component (g) Internal PhaseAcetochlor 352.7 NORPAR 18.41 DES N3200 12.59 DES W 12.59 External PhaseGlycerin 64.50 SOKALAN CP9 19.0 Ammonium Caseinate 0.4 Acid 1.39 Water232.3 TETA, 50% solution 7.1 7.1 Stabilizer Invalon 47.89 Kelzan CC 0.43Antifoam 0.01 Glycerin 32.10 Proxel GXL 0.43 Caustic 0.15 Buffer 0.96

The aqueous dispersions of microcapsules were prepared substantially asdescribed above in Example 1. To prepare each formulation, the largeinternal phase, external phase, and stabilizer batches were divided intosmaller approximately equal weight batches and combined as described inExample 1. Two separate amine solutions were used to initiatepolymerization. During emulsification, the mixer speed was varied bycontrolling the blender to achieve mean particle sizes as shown in thetable:

TABLE Particle Size Parameters Formulations Mean Particle size (μm)Standard Deviation (μm) 911A 7.73 5.64 911B 2.62 2.94

Example 17. Preparation of Aqueous Dispersions of MicroencapsulatedAcetochlor

Two aqueous dispersions of microencapsulated acetochlor (designatedformulations 914A and 914C) were prepared. These formulations wereprepared using a polyisocyanate blend of DES N3200 and DES W in anapproximately 85:15 weight ratio. The polyisocyanates and TETA amineused to prepare the shell wall were added in amounts at molarequivalents ratios of amine molar equivalents to isocyanate molarequivalents of approximately 1.2:1. The mean particle sizes of each thevarious formulations were controlled varying the mixing speed duringemulsification.

To prepare these formulations, large batches of each of the internalphase, the external phase, the amine solution, and the stabilizersolution were prepared containing the components and amounts shown inthe following table:

Form. 914A Form. 914C Component Weight of Component (g) Internal PhaseAcetochlor 352.70 NORPAR 18.40 DES N3200 21.99 DES W 4.0 External PhaseGlycerin 64.6 SOKALAN CP9 19.1 Ammonium Caseinate 0.4 Acid 1.38 Water232.77 TETA, 50% solution 6.46 6.46 Stabilizer Invalon 47.89 Kelzan CC0.43 Antifoam 0.01 Glycerin 32.10 Proxel GXL 0.43 Caustic 0.15 Buffer0.96

The aqueous dispersions of microcapsules were prepared substantially asdescribed above in Example 1. To prepare each formulation, the largeinternal phase, external phase, and stabilizer batches were divided intosmaller approximately equal weight batches and combined as described inExample 1. Two amine solutions were used to initiate polymerization.During emulsification, the mixer speed was varied by controlling theblender to achieve mean particle sizes as shown in the table:

TABLE Particle Size Parameters Formulations Mean Particle size (μm)Standard Deviation (μm) 914A 2.21 1.25 914C 7.43 5.05

Example 18. Preparation of Aqueous Dispersions of MicroencapsulatedAcetochlor

Two aqueous dispersions of microencapsulated acetochlor (designatedformulations 917A and 917B) were prepared. These formulations wereprepared using a polyisocyanate blend of DES N3200 and DES W in anapproximately 70:30 weight ratio. The polyisocyanates and TETA amineused to prepare the shell wall were added in amounts at molarequivalents ratios of amine molar equivalents to isocyanate molarequivalents of approximately 1.2:1. The mean particle sizes of each thevarious formulations were controlled varying the mixing speed duringemulsification.

To prepare these formulations, large batches of each of the internalphase, the external phase, the amine solution, and the stabilizersolution were prepared containing the components and amounts shown inthe following table:

Form. 917A Form. 917B Component Weight of Component (g) Internal PhaseAcetochlor 352.65 NORPAR 18.40 DES N3200 17.85 DES W 7.66 External PhaseGlycerin 64.57 SOKALAN CP9 19.01 Ammonium Caseinate 0.38 Acid 1.41 Water232.60 TETA, 50% solution 6.74 6.74 Stabilizer Invalon 47.89 Kelzan CC0.43 Antifoam 0.01 Glycerin 32.10 Proxel GXL 0.43 Caustic 0.15 Buffer0.96

The aqueous dispersions of microcapsules were prepared substantially asdescribed above in Example 1. To prepare each formulation, the largeinternal phase, external phase, amine, and stabilizer batches weredivided into smaller approximately equal weight batches and combined asdescribed in Example 1. During emulsification, the mixer speed wasvaried by controlling the blender to achieve mean particle sizes asshown in the table:

TABLE Particle Size Parameters Formulations Mean Particle size (μm)Standard Deviation (μm) 917A 1.99 1.1 917B 7.55 5.01

Example 19. Study of Soybean and Cotton Crop Safety and Post-EmergenceWeed Control Efficacy Using Microencapsulated Acetochlor Formulations ofthe Invention

Formulations 911A, 911B, 914A, 914C, 917A, and 917B (prepared accordingto the methods described in Examples 16, 17, and 18) were applied toglyphosate-tolerant (ROUNDUP READY) soybean (AG 4403) andglyphosate-tolerant (ROUNDUP READY) cotton (RR Flex—short to mid-seasonvariety) crops under greenhouse conditions. These formulations weretested against commercial formulations HARNESS and DEGREE. Theformulations were applied to post-emergent soybean and cotton plants andmeasured for phytotoxicity 20 DAT. The results are shown in FIG. 30(Soybean injury) and FIG. 31 (Cotton injury).

Formulations 911A, 911B, 914C, and 917B provided greater soybean safetythan DEGREE at the two higher application rates. See FIG. 30.Formulations 914A and 917A were more equivalent to DEGREE in terms ofcrop safety. HARNESS was most injurious to soybeans; however, this studyshowed greater cotton injury with DEGREE than with HARNESS. See FIG. 31.This relative response has also been seen under field conditions, wherethe systemic malformation of newly emerging leaves is more pronouncedwith DEGREE. Overall cotton injury in this study was fairly low.Formulation 911A showed the greatest cotton safety at all rates.Formulations 917B and 914C were also less injurious than DEGREE at twoof three application rates. Release rates were measured in the SOTAXAT-7 dissolution test apparatus according to the method describedherein. See the following table for the release rates of the testedformulations.

Formulation Release at 6 hours (ppm) Release at 24 hours (ppm) 911A 137146 911B 307 320 914A 221 321 914C 96 136 917A 278 329 917B 93 125DEGREE 130 202

Formulations 911A, 911B, 914A, 914C, 917A, and 917B were also tested forweed control efficacy and compared to the weed control efficacy of bothDEGREE and HARNESS. The weed species tested included Redroot pigweed(Amaranthus retroflexus), Barnyardgrass (Echinochloa crus-galli), andYellow foxtail (Setaria lutescens). The weed control efficacy data arepresented in FIGS. 32, 33, and 34.

The weed control efficacy study showed Formulation 911A to besubstantially less effective than DEGREE at all application rates. SeeFIGS. 32, 33, and 34. Formulation 917B was slightly less effective thanDEGREE, while Formulation 914C was nearly equivalent. All otherformulations were better than or equal to DEGREE.

These data show that increased particle size continues to have thebiggest influence on improved crop safety with encapsulated acetochlorformulations. Increasing the level of amine in these formulations didnot dramatically impact crop safety, but did show a more significantinfluence on weed control efficacy.

Example 20. Preparation of Aqueous Dispersions of MicroencapsulatedAcetochlor

Two aqueous dispersions of microencapsulated acetochlor (designatedformulations 934 and 939) were prepared. These formulations wereprepared using the MISTAFLEX blend comprising DES N3200 and DES W and asingle amine, TETA. The molar equivalents ratio of amine molarequivalents to isocyanate molar equivalents was approximately 1.05:1.Additionally, the internal solvent was changed from NORPAR 15 to ISOPARL. Formulation 939 was prepared with a relatively higher proportion ofISOPAR L solvent compared to formulation 934.

To prepare these formulations, the internal phase, the external phase,the amine solution, and the stabilizer solution were prepared containingthe components and amounts shown in the following table:

Form. 934 Form. 939 Component Weight of Component (g) Internal PhaseAcetochlor 175.50 174.20 ISOPAR L 9.10 18.20 MISTAFLEX H9915 13.06 13.70External Phase Glycerin 32.0 30.00 SOKALAN CP9 9.57 8.90 AmmoniumCaseinate 0.20 0.18 Acid 0.75 0.75 Water 116.0 108 TETA, 50% solution5.79 6.08 Stabilizer Invalon 23.65 23.65 Kelzan CC 0.21 0.21 Antifoam 00 Glycerin 15.85 15.85 Proxel GXL 0.21 0.21 Caustic 0.07 0.07 Buffer0.47 0.47

The aqueous dispersions of microcapsules were prepared substantially asdescribed above in Example 1. During emulsification, the mixer speed wasvaried by controlling the blender to achieve mean particle sizes asshown in the table:

TABLE Particle Size Parameters Formulations Mean Particle size (μm)Standard Deviation (μm) 934 10.69 8.33 939 9.75 5.96

Example 21. Preparation of Aqueous Dispersions of MicroencapsulatedAcetochlor

Two aqueous dispersions of microencapsulated acetochlor (designatedformulations 936A and 936B) were prepared. These formulations wereprepared using the MISTAFLEX blend comprising DES N3200 and DES W and asingle amine, TETA. The molar equivalents ratio of amine molarequivalents to isocyanate molar equivalents was approximately 1.05:1.Additionally, the internal solvent was changed from NORPAR 15 to ISOPARL. The mean particle sizes of each the various formulations werecontrolled varying the mixing speed during emulsification.

To prepare these formulations, large batches of each of the internalphase, the external phase, the amine solution, and the stabilizersolution were prepared containing the components and amounts shown inthe following table:

Form. 936A Form. 936B Component Weight of Component (g) Internal PhaseAcetochlor 352.70 ISOPAR L 18.40 MISTAFLEX H9915 26.40 External PhaseGlycerin 64.70 SOKALAN CP9 19.10 Ammonium Caseinate 0.38 Acid 1.42 Water233.3 TETA, 50% solution 5.79 5.79 Stabilizer Invalon 47.89 Kelzan CC0.43 Antifoam 0.01 Glycerin 32.10 Proxel GXL 0.43 Caustic 0.15 Buffer0.96

The aqueous dispersions of microcapsules were prepared substantially asdescribed above in Example 1. To prepare each formulation, the largeinternal phase, external phase, and stabilizer batches were divided intosmaller approximately equal weight batches and combined as described inExample 1. Two separate amine solutions were used to initiatepolymerization. During emulsification, the mixer speed was varied bycontrolling the blender to achieve mean particle sizes as shown in thetable:

TABLE Particle Size Parameters Formulations Mean Particle size (μm)Standard Deviation (μm) 936A 10.16 6.34 936B 8.36 5.46

Example 22. Preparation of Aqueous Dispersions of MicroencapsulatedAcetochlor

Three aqueous dispersions of microencapsulated acetochlor (designatedformulations 941A, 941B, and 941C) were prepared. These formulationswere prepared using the MISTAFLEX blend comprising DES N3200 and DES Wand a single amine, TETA. The molar equivalents ratio of amine molarequivalents to isocyanate molar equivalents was approximately 1.05:1.Additionally, the internal solvent was changed from NORPAR 15 to ISOPARV. The mean particle sizes of each the various formulations werecontrolled varying the mixing speed during emulsification.

To prepare these formulations, large batches of each of the internalphase, the external phase, the amine solution, and the stabilizersolution were prepared containing the components and amounts shown inthe following table:

Form. 941A Form. 941B Form. 941C Component Weight of Component (g)Internal Phase Acetochlor 529.0 ISOPAR V 55.30 MISTAFLEX H9915 41.6External Phase Glycerin 90.90 SOKALAN CP9 26.80 Ammonium Caseinate 0.54Acid 2.09 Water 327.60 TETA, 50% solution 6.09 6.10 6.10 StabilizerInvalon 71.83 Kelzan CC 0.64 Antifoam 0.01 Glycerin 48.15 Proxel GXL0.64 Caustic 0.22 Buffer 1.43

The aqueous dispersions of microcapsules were prepared substantially asdescribed above in Example 1. To prepare each formulation, the largeinternal phase, external phase, and stabilizer batches were divided intosmaller approximately equal weight batches and combined as described inExample 1. Three separate amine solutions were used to initiatepolymerization. During emulsification, the mixer speed was varied bycontrolling the blender to achieve mean particle sizes as shown in thetable:

TABLE Particle Size Parameters Formulations Mean Particle size (μm)Standard Deviation (μm) 941A 8.90 5.56 941B 11.67 6.76 941C 10.98 6.52

Example 23. Preparation of Aqueous Dispersions of MicroencapsulatedAcetochlor

Three aqueous dispersions of microencapsulated acetochlor (designatedformulations 945A, 945B, and 945C) were prepared. These formulationswere prepared using the MISTAFLEX blend comprising DES N3200 and DES Wand a single amine, TETA. The molar equivalents ratio of amine molarequivalents to isocyanate molar equivalents was approximately 1.05:1.Additionally, the internal solvent was changed from NORPAR 15 to ISOPARV, and in this Example, the relative proportion of ISOPAR V was halvedcompared to Example 22. The mean particle sizes of each the variousformulations were controlled varying the mixing speed duringemulsification.

To prepare these formulations, large batches of each of the internalphase, the external phase, the amine solution, and the stabilizersolution were prepared containing the components and amounts shown inthe following table:

Forms. 945A, 945B, 945C Component Weight of Component (g) Internal PhaseAcetochlor 529.0 ISOPAR V 27.65 MISTAFLEX H9915 39.60 External PhaseGlycerin 97.1 SOKALAN CP9 28.7 Ammonium Caseinate 0.57 Acid 2.25 Water350 TETA, 50% solution 17.6 Stabilizer Invalon 71.83 Kelzan CC 0.64Antifoam 0.01 Glycerin 48.15 Proxel GXL 0.64 Caustic 0.22 Buffer 1.43

The aqueous dispersions of microcapsules were prepared substantially asdescribed above in Example 1. To prepare each formulation, the largeinternal phase, external phase, amine, and stabilizer batches weredivided into smaller approximately equal weight batches and combined asdescribed in Example 1. During emulsification, the mixer speed wasvaried by controlling the blender to achieve mean particle sizes asshown in the table:

TABLE Particle Size Parameters Formulations Mean Particle size (μm)Standard Deviation (μm) 945A 9.72 6.02 945B 13.22 8.23 945C 12.48 7.84

Example 24. Preparation of Aqueous Dispersions of MicroencapsulatedAcetochlor

An aqueous dispersion of microencapsulated acetochlor (designatedformulation 949) was prepared. Formulation 949 was prepared usingMISTAFLEX and TETA amine at molar equivalents ratios of amine molarequivalents to isocyanate molar equivalents of approximately 1.05:1.Additionally, the internal solvent was changed from NORPAR 15 to ExxsolD-130, and a relatively small proportion of Exxsol D-130 was used.

To prepare the formulation, the internal phase, the external phase, theamine solution, and the stabilizer solution were prepared containing thecomponents and amounts shown in the following table:

Component Weight of Component (g) Internal Phase Acetochlor 174.25Exxsol D-130 9.1 MISTAFLEX H9915 13.1 External Phase Glycerin 32.0SOKALAN CP9 9.5 Ammonium Caseinate 0.2 Acid 0.75 Water 115.3 TETA, 50%solution 5.8 Stabilizer Invalon 23.65 Kelzan CC 0.21 Antifoam 0 Glycerin15.85 Proxel GXL 0.21 Caustic 0.07 Buffer 0.47

The aqueous dispersion of microcapsules was prepared substantially asdescribed above in Example 1 and had a mean particle size of 10.59 μmand a standard deviation of 6.45 μm.

Example 25. Preparation of Aqueous Dispersions of MicroencapsulatedAcetochlor

Two aqueous dispersions of microencapsulated acetochlor (designatedformulations 951A and 951B) were prepared. These formulations wereprepared using the MISTAFLEX blend comprising DES N3200 and DES W and asingle amine, TETA. The molar equivalents ratio of amine molarequivalents to isocyanate molar equivalents was approximately 1.05:1.Additionally, the internal solvent was changed from NORPAR 15 to ISOPARV, and in this Example, the relative proportion of ISOPAR V was halvedcompared to Example 22. The mean particle sizes of each the variousformulations were controlled varying the mixing speed duringemulsification.

To prepare these formulations, large batches of each of the internalphase, the external phase, the amine solution, and the stabilizersolution were prepared containing the components and amounts shown inthe following table:

Form. 951A and 951B Component Weight of Component (g) Internal PhaseAcetochlor 352.70 ISOPAR V 18.42 MISTAFLEX H9915 26.40 External PhaseGlycerin 64.70 SOKALAN CP9 19.10 Ammonium Caseinate 0.39 Acid 1.45 Water233.3 TETA, 50% solution 11.73 Stabilizer Invalon 47.89 Kelzan CC 0.43Antifoam 0.01 Glycerin 32.10 Proxel GXL 0.43 Caustic 0.15 Buffer 0.96

The aqueous dispersions of microcapsules were prepared substantially asdescribed above in Example 1. To prepare each formulation, the largeinternal phase, external phase, amine, and stabilizer batches weredivided into smaller approximately equal weight batches and combined asdescribed in Example 1. During emulsification, the mixer speed wasvaried by controlling the blender to achieve mean particle sizes asshown in the table:

TABLE Particle Size Parameters Formulations Mean Particle size (μm)Standard Deviation (μm) 951A 11.28 7.53 951B 8.30 5.48

Example 26. Preparation of Aqueous Dispersions of MicroencapsulatedAcetochlor

Two aqueous dispersions of microencapsulated acetochlor (designatedformulations 954A and 954B) were prepared. These formulations wereprepared using the MISTAFLEX blend comprising DES N3200 and DES W and asingle amine, TETA. The molar equivalents ratio of amine molarequivalents to isocyanate molar equivalents was approximately 1.05:1.Additionally, the internal solvent was changed from NORPAR 15 to ExxsolD-130. The mean particle sizes of each the various formulations werecontrolled varying the mixing speed during emulsification.

To prepare these formulations, large batches of each of the internalphase, the external phase, the amine solution, and the stabilizersolution were prepared containing the components and amounts shown inthe following table:

Form. 954A and 954B Component Weight of Component (g) Internal PhaseAcetochlor 352.7 Exxsol D-130 36.85 MISTAFLEX 27.71 External PhaseGlycerin 60.80 SOKALAN CP9 17.9 Ammonium Caseinate 0.37 Acid 1.28 Water218.39 TETA, 50% solution 12.31 Stabilizer Invalon 47.89 Kelzan CC 0.43Antifoam 0.01 Glycerin 32.10 Proxel GXL 0.43 Caustic 0.15 Buffer 0.96

The aqueous dispersions of microcapsules were prepared substantially asdescribed above in Example 1. To prepare each formulation, the largeinternal phase, external phase, amine, and stabilizer batches weredivided into smaller approximately equal weight batches and combined asdescribed in Example 1. During emulsification, the mixer speed wasvaried by controlling the blender to achieve mean particle sizes asshown in the table:

TABLE Particle Size Parameters Formulations Mean Particle size (μm)Standard Deviation (μm) 954A 9.83 6.04 954B 7.7

Example 27. Preparation of Aqueous Dispersions of MicroencapsulatedAcetochlor

Two aqueous dispersions of microencapsulated acetochlor (designatedformulations 957A and 957B) were prepared. These formulations wereprepared using the MISTAFLEX blend comprising DES N3200 and DES W and asingle amine, TETA. The molar equivalents ratio of amine molarequivalents to isocyanate molar equivalents was approximately 1.05:1.Additionally, the internal solvent was changed from NORPAR 15 to ISOPARL. The mean particle sizes of each the various formulations werecontrolled varying the mixing speed during emulsification.

To prepare these formulations, large batches of each of the internalphase, the external phase, the amine solution, and the stabilizersolution were prepared containing the components and amounts shown inthe following table:

Forms. 957A and 957B Component Weight of Component (g) Internal PhaseAcetochlor 353.0 ISOPAR L 36.90 MISTAFLEX H9915 27.7 External PhaseGlycerin 60.6 SOKALAN CP9 17.9 Ammonium Caseinate 0.37 Acid 1.35 Water218.40 TETA, 50% solution 12.31 Stabilizer Invalon 47.89 Kelzan CC 0.43Antifoam 0.01 Glycerin 32.10 Proxel GXL 0.43 Caustic 0.15 Buffer 0.96

The aqueous dispersions of microcapsules were prepared substantially asdescribed above in Example 1. To prepare each formulation, the largeinternal phase, external phase, amine, and stabilizer batches weredivided into smaller approximately equal weight batches and combined asdescribed in Example 1. During emulsification, the mixer speed wasvaried by controlling the blender to achieve mean particle sizes asshown in the table:

TABLE Particle Size Parameters Formulations Mean Particle size (μm)Standard Deviation (μm) 957A 10.46 6.38 957B 8.01 5.13

Example 28. Preparation of Aqueous Dispersions of MicroencapsulatedAcetochlor

Two aqueous dispersions of microencapsulated acetochlor (designatedformulation 960A and 960B) were prepared. These formulations wereprepared using the MISTAFLEX blend comprising DES N3200 and DES W and asingle amine, TETA. The molar equivalents ratio of amine molarequivalents to isocyanate molar equivalents was approximately 1.05:1.Additionally, the internal solvent was changed from NORPAR 15 to ExxsolD-130, and a higher proportion of Exxsol D-130 was used compared toExample 22.

To prepare the formulation, large batches of each of the internal phase,the external phase, the amine solution, and the stabilizer solution wereprepared containing the components and amounts shown in the followingtable:

Form. 960A Form. 960B Component Weight of Component (g) Internal PhaseAcetochlor 352.70 Exxsol D-130 36.83 MISTAFLEX H9915 27.70 ExternalPhase Glycerin 60.6 SOKALAN CP9 17.9 Ammonium Caseinate 0.37 Acid 1.35Water 218.40 TETA, 50% solution 6.10 6.09 Stabilizer Invalon 47.89Kelzan CC 0.43 Antifoam 0.01 Glycerin 32.10 Proxel GXL 0.43 Caustic 0.15Buffer 0.96

The aqueous dispersions of microcapsules were prepared substantially asdescribed above in Example 1. To prepare each formulation, the largeinternal phase, external phase, and stabilizer batches were divided intosmaller approximately equal weight batches and combined as described inExample 1. Two separate amine solutions were used to initiatepolymerization. During emulsification, the mixer speed was varied bycontrolling the blender to achieve mean particle sizes as shown in thetable:

TABLE Particle Size Parameters Formulations Mean Particle size (μm)Standard Deviation (μm) 960A 10.60 6.51 960B 6.65 4.55

Example 29. Study of Soybean and Cotton Crop Safety and Post-EmergenceWeed Control Efficacy Using Microencapsulated Acetochlor Formulations ofthe Invention

Formulations 934, 936B, 941C, 951B, and 954B (prepared according to themethods described in Examples 20, 21, 22, 25, and 26) were applied toglyphosate-tolerant (ROUNDUP READY) soybean (AG 4403) andglyphosate-tolerant (ROUNDUP READY) cotton (RR Flex—short to mid-seasonvariety) crops under greenhouse conditions. These formulations weretested against commercial formulations HARNESS, DEGREE, and DUAL IIMAGNUM. The formulations were applied to post-emergent soybean andcotton plants and measured for phytotoxicity 14 DAT. The results areshown in FIG. 35 (Soybean injury) and FIG. 36 (Cotton injury).

The formulations in this study had increased capsule size compared toDEGREE (capsule size of approximately 3 μm) and different solventswithin the capsule (Norpar is used to formulate DEGREE). Allformulations provided better soybean safety than DEGREE withformulations 934, 941C, and 954B showing the least amount of injury. SeeFIG. 35. All formulations also showed less cotton injury than DEGREE,but only at the highest rate tested. See FIG. 36. Release rates weremeasured in a SOTAX AT-7 dissolution test apparatus according to themethod described herein. See the following table for the release ratesof the tested formulations.

Formulation Release at 6 hours (ppm) Release at 24 hours (ppm) 934 58 73936B 70 90 941C 52 63 951B 78 95 954B 54 63 DEGREE 129 179

Formulations 934, 936B, 941C, 951B, 949 (formulated as describe above inExample 24), 954B were also tested for weed control efficacy andcompared to the weed control efficacy of both DEGREE and HARNESS. Theweed species tested included Redroot pigweed (Amaranthus retroflexus),Barnyardgrass (Echinochloa crus-galli), and Yellow foxtail (Setarialutescens). The weed control efficacy data are presented in FIGS. 37,38, and 39.

Pre-emergence weed control with these formulations highlighted a numberof differences among these formulations. Redroot pigweed control showedformulations 934, 949, and 954B to be less effective than DEGREE at thetwo higher application rates. See FIG. 37. The remaining formulationsprovided control that was equivalent or greater than that shown byDEGREE. Note the lack of control with DUAL II MAGNUM. Barnyardgrass,probably the most reliable indicator in this assay, showed weakercontrol with formulations 934 and 941C at the two lower applicationrates. See FIG. 38. All other formulations were closely equivalent toDEGREE. Control of yellow foxtail again indicated some weakness withFormulation 941C. See FIG. 39. Weaker control was also seen withformulations 936B and 949 at the lowest rate tested. All formulationswere clearly superior to Dual Magnum in the control of redroot pigweed,differences were less apparent versus the grass weed species in thisstudy.

Example 30. Study of Soybean and Cotton Crop Safety and Post-EmergenceWeed Control Efficacy Using Microencapsulated Acetochlor Formulations ofthe Invention

Formulations 941B, 945A, 945C, 951A, 957A, and 960A (prepared accordingto the methods described in Examples 22, 23, 25, 27, and 28) wereapplied to glyphosate-tolerante (ROUNDUP READY) soybean (AG 4403) andglyphosate-tolerant (ROUNDUP READY) cotton (RR Flex—short to mid-seasonvariety) crops under greenhouse conditions. These formulations weretested against commercial formulations HARNESS, DEGREE, and DUAL IIMAGNUM. The formulations were applied to post-emergent soybean andcotton plants and measured for phytotoxicity 14 DAT. The results areshown in FIG. 40 (Cotton injury) and FIG. 41 (Soybean injury).

These formulations again contained larger capsule sizes and differentsolvents within the capsule. All formulations provided better cottonsafety than DEGREE at all application rates. See FIG. 40. The best cropsafety was evident with Formulations 941B, 957A, and 960A. Differenceswere less apparent in soybeans due to less overall injury. See FIG. 41.However, formulations 941B and 960A again showed significantly lessinjury than DEGREE at all application rates. Release rates were measuredin a SOTAX AT-7 dissolution test apparatus according to the methoddescribed herein. See the following table for the release rate offormulation 960A and of DEGREE.

Formulation Release at 6 hours (ppm) Release at 24 hours (ppm) 960A 5264 DEGREE 129 179

Formulations 941B, 945A, 945C, 951A, 957A, and 980A were also tested forweed control efficacy and compared to the weed control efficacy of bothDEGREE and HARNESS. The weed species tested included Redroot pigweed(Amaranthus retroflexus), Barnyardgrass (Echinochloa crus-galli), andYellow foxtail (Setaria lutescens). The weed control efficacy data arepresented in FIGS. 42, 43, and 44. All experimental formulations in thisstudy provided more complete control of yellow foxtail across allapplication rates. See FIG. 42. Relative to barnyardgrass, onlyformulations 951A and 960A gave control equivalent to DEGREE at allrates. See FIG. 43. Control of redroot pigweed was greater than DEGREEwith formulations 954A, 957A, and 960A. See FIG. 44. All others wereessentially equivalent.

Example 31. Study of Soybean and Cotton Crop Safety and Post-EmergenceWeed Control Efficacy Using Microencapsulated Acetochlor Formulations ofthe Invention

Formulations 939, 941A, 954A, 957B and 960B (prepared according to themethods described in Examples 20, 22, 26, 27, and 28) were applied toglyphosate-tolerant (ROUNDUP READY) soybean (AG 4403) andglyphosate-tolerant (ROUNDUP READY) cotton (RR Flex—short to mid-seasonvariety) crops under greenhouse conditions. These formulations weretested against commercial formulations HARNESS, DEGREE, and DUAL IIMAGNUM. The formulations were applied to post-emergent soybean andcotton plants and measured for phytotoxicity 13 DAT. The results areshown in FIG. 45 (soybean injury) and FIG. 46 (cotton injury).Formulations 957B and 960B were both slightly less injurious than DEGREEversus soybeans and significantly less injurious versus cotton at allrates. See FIGS. 45 and 46. All other formulations were also lessinjurious than DEGREE, but lacked sufficient efficacy to be of furtherinterest. See below. Release rates were measured in a SOTAX AT-7dissolution test apparatus according to the method described herein. Seethe following table for the release rates of some of the testedformulations.

Formulation Release at 6 hours (ppm) Release at 24 hours (ppm) 941A 5664 954A 53 64 957B 68 87 960B 70 86 DEGREE 129 179

Formulations 939, 941A, 954A, 957B and 960B were also tested for weedcontrol efficacy and compared to the weed control efficacy of DEGREE,HARNESS, and DUAL II MAGNUM. The weed species tested included Redrootpigweed (Amaranthus retroflexus), Barnyardgrass (Echinochloacrus-galli), Yellow foxtail (Setaria lutescens), and Purslane. The weedcontrol efficacy data are presented in FIGS. 47 through 50.Pre-emergence weed control with these experimental formulations showed957B and 960B to have efficacy equal to or better than that of DEGREEacross all species. See FIGS. 47 through 50.

Example 32. Study of Soybean and Cotton Crop Safety and Post-EmergenceWeed Control Efficacy Using Microencapsulated Acetochlor Formulations ofthe Invention

Formulations 936B, 941B, 951B, 957B, 960A, and 960B (prepared accordingto the methods described in Examples 21, 22, 25, 27, and 28) wereapplied to glyphosate-tolerant (ROUNDUP READY) soybean (AG 4403) andglyphosate-tolerant (ROUNDUP READY) cotton (RR Flex—short to mid-seasonvariety) crops under greenhouse conditions. These formulations weretested against commercial formulations HARNESS, DEGREE, DUAL II MAGNUM,and TOPNOTCH, available from Dow AgroSciences. TOPNOTCH contains 33.7%acetochlor and 66.3% proprietary ingredients, including dichlormid. Theformulations were applied to post-emergent soybean and cotton plants andmeasured for phytotoxicity. The results are shown in FIG. 51 (soybeaninjury 19 DAT), FIG. 52 (cotton injury 19 DAT), FIG. 53 (cotton injury15 DAT), and FIG. 54 (soybean injury 15 DAT).

Formulations 936B, 941B, 951B, and 960A were evaluated against HARNESS,DEGREE, DUAL II MAGNUM, and formulation 3997 (prepared according to themethod described in Example 3). The best crop safety among formulations936B, 941B, 951B, and 960A in this study was seen with formulation 941B.See FIGS. 51 and 52. This formulation showed significantly better cottonand soybean safety than DEGREE at all application rates. Formulations936B, 951B, and 960A were generally equivalent to formulation 3997. Theyshowed similar soybean injury to that observed with DEGREE, but weresignificantly safer at all rates in cotton. The one exception wasFormulation 936B, which was similar to DEGREE in cotton at the highapplication rate. Release rates were measured in a SOTAX AT-7dissolution test apparatus according to the method described herein. Seethe following table for the release rates of some of the testedformulations.

Formulation Release at 6 hours (ppm) Release at 24 hours (ppm) 936B 7090 951B 78 95 960A 52 64 960B 70 86 DEGREE 129 179

Formulations 957B and 960B were evaluated in this study versus DEGREE,DUAL II MAGNUM, TOPNOTCH, and formulation 3997. Both formulations showedsoybean and cotton safety that was equivalent to that seen withformulation 3997. See FIGS. 53 and 54. All three of these formulationswere substantially safer than the commercial standards. TOPNOTCH provedto be the most injurious formulation.

Formulations 936B, 941B, 951B, 957B, 960A, and 960B were also tested forweed control efficacy and compared to the weed control efficacy ofDEGREE, HARNESS, DUAL II MAGNUM, and formulation 3997. The weed speciestested included Redroot pigweed (Amaranthus retroflexus), Barnyardgrass(Echinochloa crus-galli), Yellow foxtail (Setaria lutescens), andPurslane (Portulaca oleracea). The weed control efficacy data arepresented in FIGS. 53 through 56.

Formulations 941B and 960A were both substantially less effective incontrolling barnyardgrass and yellow foxtail than the commercialstandards. See FIGS. 53 and 54. Formulations 951B and 936B were betterthan or equal to formulation 3997 in weed control efficacy. Among thesethree the best weed control was obtained with Formulation 936B.

Example 33. Study of Soybean and Cotton Crop Safety and Post-EmergenceWeed Control Efficacy Using Microencapsulated Acetochlor Formulations ofthe Invention

Formulations 957B, 960B, 951B, and 936B (prepared according to themethods described in Examples 21, 25, 27, and 28) were applied toglyphosate-tolerant (ROUNDUP READY) soybean (AG 4403) andglyphosate-tolerant (ROUNDUP READY) cotton (RR Flex—short to mid-seasonvariety) crops under greenhouse conditions. These formulations weretested against commercial formulations HARNESS, DEGREE, and DUAL IIMAGNUM and against formulation 3997 (prepared as described in Example3). The formulations were applied to post-emergent soybean and cottonplants and measured for phytotoxicity 15 DAT. The results are shown inFIG. 57 (soybean injury) and FIG. 58 (cotton injury).

Post-emergence soybean injury showed all four experimental formulationsto be equivalent to formulation 3997. See FIG. 57. These showedsignificantly better crop safety than DEGREE and DUAL II MAGNUM at thehigh rate and HARNESS at all application rates. Cotton injury for theexperimental formulations was similar to that of formulation 3997 andsignificantly better than HARNESS and DUAL II MAGNUM at the two highestrates and DEGREE at the highest rate. See FIG. 58. Release rates weremeasured in a SOTAX AT-7 dissolution test apparatus according to themethod described herein. See the following table for the release ratesof the tested formulations.

Formulation Release at 6 hours (ppm) Release at 24 hours (ppm) 957B 6887 960B 70 86 951B 78 95 936B 70 90 DEGREE 129 179

Formulations 957B, 960B, 951B, and 936B were also tested for weedcontrol efficacy and compared to the weed control efficacy of DEGREE,HARNESS, and DUAL II MAGNUM. The weed species tested includedBarnyardgrass (Echinochloa crus-galli), Yellow foxtail (Setarialutescens), and Annual ryegrass (Lolium multiflorum). The weed controlefficacy data are presented in FIGS. 59 through 61.

Formulations 936B and 951B consistently provided the best weed controlefficacy across species among the experimental formulations. Relative toyellow foxtail these two formulations gave control that was equal toHARNESS, better than DEGREE, and marginally better than formulation 3997and DUAL II MAGNUM. See FIG. 59. Formulations 957B and 960B were bothequal to formulation 3997 at higher rates, but were weaker at the lowestrate. Formulations 936B, 951B, and 957B were equal to or better than thestandards at most application rates in the control of barnyardgrass. SeeFIG. 60. Formulation 960B was less effective. Control of perennialryegrass showed Formulations 936B, 951B, and 960B to be equal to DEGREEand formulation 3997. See FIG. 59. Formulation 957B in this case wasless effective.

Example 34. Preparation of Aqueous Dispersions of MicroencapsulatedAcetochlor

Three aqueous dispersions of microencapsulated acetochlor (designatedformulation 993A, 993B, and 993C) were prepared. These formulations wereprepared using the MISTAFLEX blend comprising DES N3200 and DES W and asingle amine, TETA. The molar equivalents ratio of amine molarequivalents to isocyanate molar equivalents was approximately 1.2:1. Inthese formulations, the acetochlor loading approximately 38% by weight,which is relatively lower than the acetochlor loading in DEGREE.

To prepare the formulation, large batches of each of the internal phase,the external phase, the amine solution, and the stabilizer solution wereprepared containing the components and amounts shown in the followingtable:

Form. 993A Form. 993B Form. 993C Component Weight of Component (g)Internal Phase Acetochlor 483.0 NORPAR 15 25.0 MISTAFLEX H9915 35.20External Phase Glycerin 108.0 SOKALAN CP9 31.82 Ammonium Caseinate 0.64Acid 2.40 Water 389.0 TETA, 50% solution 5.90 5.87 5.86 StabilizerInvalon 71.83 Kelzan CC 0.64 Antifoam 0.01 Glycerin 48.15 Proxel GXL0.64 Caustic 0.22 Buffer 1.43

The aqueous dispersions of microcapsules were prepared substantially asdescribed above in Example 1. To prepare each formulation, the largeinternal phase, external phase, and stabilizer batches were divided intosmaller approximately equal weight batches and combined as described inExample 1. Three separate amine solutions were used to initiatepolymerization. During emulsification, the mixer speed was varied bycontrolling the blender to achieve mean particle sizes as shown in thetable:

TABLE Particle Size Parameters Formulations Mean Particle size (μm)Standard Deviation (μm) 993A 7.86 5.36 993B 10.95 6.64 993C 13.9 10.4

Example 35. Preparation of Aqueous Dispersions of MicroencapsulatedAcetochlor

Three aqueous dispersions of microencapsulated acetochlor (designatedformulation 997A, 997B, and 997C) were prepared. These formulations wereprepared using the MISTAFLEX blend comprising DES N3200 and DES W and asingle amine, TETA. The molar equivalents ratio of amine molarequivalents to isocyanate molar equivalents was approximately 1.2:1. Inthese formulations, the acetochlor loading approximately 40% by weight,which is relatively lower than the acetochlor loading in DEGREE.

To prepare the formulation, large batches of each of the internal phase,the external phase, the amine solution, and the stabilizer solution wereprepared containing the components and amounts shown in the followingtable:

Form. 997A Form. 997B Form. 997C Component Weight of Component (g)Internal Phase Acetochlor 508.40 NORPAR 15 26.30 MISTAFLEX H9915 37.10External Phase Glycerin 101.90 SOKALAN CP9 30.05 Ammonium Caseinate 0.61Acid 2.25 Water 367.0 TETA, 50% solution 6.21 6.23 6.22 StabilizerInvalon 71.83 Kelzan CC 0.64 Antifoam 0.01 Glycerin 48.15 Proxel GXL0.64 Caustic 0.22 Buffer 1.43

The aqueous dispersions of microcapsules were prepared substantially asdescribed above in Example 1. To prepare each formulation, the largeinternal phase, external phase, amine, and stabilizer batches weredivided into smaller approximately equal weight batches and combined asdescribed in Example 1. During emulsification, the mixer speed wasvaried by controlling the blender to achieve mean particle sizes asshown in the table:

TABLE Particle Size Parameters Formulations Mean Particle size (μm)Standard Deviation (μm) 997A 7.73 5.17 997B 10.56 6.66 997C 13.38 9.21

Example 36. Preparation of Aqueous Dispersions of MicroencapsulatedAcetochlor

Three aqueous dispersions of microencapsulated acetochlor (designatedformulation 601A, 601B, and 601C) were prepared. These formulations wereprepared using the MISTAFLEX blend comprising DES N3200 and DES W and asingle amine, TETA. The molar equivalents ratio of amine molarequivalents to isocyanate molar equivalents was approximately 1.2:1. Inthese formulations, the acetochlor loading was approximately equal toDEGREE.

To prepare the formulation, large batches of each of the internal phase,the external phase, the amine solution, and the stabilizer solution wereprepared containing the components and amounts shown in the followingtable:

Form. 601A Form. 601B Form. 601C Component Weight of Component (g)Internal Phase Acetochlor 534.60 NORPAR 15 27.65 MISTAFLEX H9915 39.0External Phase Glycerin 95.66 SOKALAN CP9 28.22 Ammonium Caseinate 0.58Acid 2.25 Water 345.0 TETA, 50% solution 6.54 6.53 6.54 StabilizerInvalon 71.83 Kelzan CC 0.64 Antifoam 0.01 Glycerin 48.15 Proxel GXL0.64 Caustic 0.22 Buffer 1.43

The aqueous dispersions of microcapsules were prepared substantially asdescribed above in Example 1. To prepare each formulation, the largeinternal phase, external phase, and stabilizer batches were divided intosmaller approximately equal weight batches and combined as described inExample 1. Three separate amine solutions were used to initiatepolymerization. During emulsification, the mixer speed was varied bycontrolling the blender to achieve mean particle sizes as shown in thetable:

TABLE Particle Size Parameters Formulations Mean Particle size (μm)Standard Deviation (μm) 601A 8.13 5.23 601B 11.08 7.44 601C 14.64 10.46

Example 37. Study of Soybean and Cotton Crop Safety and Post-EmergenceWeed Control Efficacy Using Microencapsulated Acetochlor Formulations ofthe Invention

Formulations 993A, 993B, 993C, 997A, 997C, and 601C (prepared accordingto the methods described in Examples 34 through 36) were applied toglyphosate-tolerant (ROUNDUP READY) soybean (AG 4403) andglyphosate-tolerant (ROUNDUP READY) cotton (RR Flex—short to mid-seasonvariety) crops under greenhouse conditions. These formulations weretested against commercial formulations HARNESS, DEGREE, and DUAL IIMAGNUM. The formulations were applied to post-emergent soybean andcotton plants and measured for phytotoxicity 14 DAT. The results areshown in FIG. 62 (cotton injury) and FIG. 63 (soybean injury).

All experimental formulations demonstrated significantly less soybeaninjury than DEGREE at the two higher application rates. Cotton injuryshowed three formulations, 993A, 993C, and 997A to be as injurious asDEGREE at the highest application rate. Release rates were measured in aSOTAX AT-7 dissolution test apparatus according to the method describedherein. See the following table for the release rates of the testedformulations.

Formulation Release at 6 hours (ppm) Release at 24 hours (ppm) 993A 81108 993B 64 86 993C 50 69 997A 79 106 997C 53 73 601C 74 94 DEGREE 134217

Formulations 993A, 993B, 993C, 997A, 997C, and 601C were also tested forweed control efficacy and compared to the weed control efficacy ofDEGREE, HARNESS, and DUAL II MAGNUM. The weed species tested wereBarnyardgrass (Echinochloa crus-galli) and Yellow foxtail (Setarialutescens). The weed control efficacy data are presented in FIGS. 64 and65.

Formulation 993A was the only formulation to provide barnyardgrasscontrol that was equivalent to DEGREE at all application rates. See FIG.64. Yellow foxtail control showed Formulations 993A and 993B to be equalto or better than DEGREE. See FIG. 65. Weakest activity across these twospecies was seen with Formulations 997C and 601C. There was a cleartrend toward lower efficacy as capsule size increased.

Example 38. Preparation of Aqueous Dispersions of MicroencapsulatedAcetochlor

Three aqueous dispersions of microencapsulated acetochlor (designatedformulation 609A, 609B, and 609C) were prepared. These formulations wereprepared using the MISTAFLEX blend comprising DES N3200 and DES W and asingle amine, TETA. The molar equivalents ratio of amine molarequivalents to isocyanate molar equivalents was approximately 1.2:1. Inthese formulations, the acetochlor loading approximately 33% by weight,which is relatively lower than the acetochlor loading in DEGREE.

To prepare the formulation, large batches of each of the internal phase,the external phase, the amine solution, and the stabilizer solution wereprepared containing the components and amounts shown in the followingtable:

Form. 609A Form. 609B Form. 609C Component Weight of Component (g)Internal Phase Acetochlor 418.10 NORPAR 15 21.70 MISTAFLEX H9915 30.56External Phase Glycerin 123.10 SOKALAN CP9 36.32 Ammonium Caseinate 0.74Acid 2.84 Water 443.6 TETA, 50% solution 5.12 5.11 5.13 StabilizerInvalon 71.83 Kelzan CC 0.64 Antifoam 0.01 Glycerin 48.15 Proxel GXL0.64 Caustic 0.22 Buffer 1.43

The aqueous dispersions of microcapsules were prepared substantially asdescribed above in Example 1. To prepare each formulation, the largeinternal phase, external phase, amine, and stabilizer batches weredivided into smaller approximately equal weight batches and combined asdescribed in Example 1. During emulsification, the mixer speed wasvaried by controlling the blender to achieve mean particle sizes asshown in the table:

TABLE Particle Size Parameters Formulations Mean Particle size (μm)Standard Deviation (μm) 609A 3.28 2.63 609B 11.61 7.22 609C 12.65 7.66

Example 39. Study of Soybean and Cotton Crop Safety and Post-EmergenceWeed Control Efficacy Using Microencapsulated Acetochlor Formulations ofthe Invention

Formulations 609A, 609B and 609C (prepared according to the methodsdescribed in Example 38) were applied to glyphosate-tolerant (ROUNDUPREADY) soybean (AG 4403) and glyphosate-tolerant (ROUNDUP READY) cotton(RR Flex—short to mid-season variety) crops under greenhouse conditions.These formulations were tested against commercial formulations HARNESS,DEGREE, DUAL II MAGNUM, and TOPNOTCH. The formulations were applied topost-emergent soybean and cotton plants and measured for phytotoxicity13 DAT. The results are shown in FIG. 66 (soybean injury) and FIG. 67(cotton injury). Formulations 609B and 609C provided the best cropsafety among experimental formulations.

Formulations 609A, 609B and 609C were also tested for weed controlefficacy and compared to the weed control efficacy of DEGREE, HARNESS,DUAL II MAGNUM, and TOPNOTCH. The weed species tested were Barnyardgrass(Echinochloa crus-galli) and Yellow foxtail (Setaria lutescens). Theweed control efficacy data are presented in FIGS. 68 and 69.

Formulation 609A provided the highest levels of weed control among theexperimental formulations. See FIGS. 68 and 69. Since this formulationhad the smallest capsule size this result is not surprising. While theother two formulations were less efficacious, they still provided weedcontrol that was comparable to DEGREE.

Example 40. Preparation of Aqueous Dispersions of MicroencapsulatedAcetochlor

Three aqueous dispersions of microencapsulated acetochlor (designatedformulation 613A, 613B, and 613C) were prepared. These formulations wereprepared using the MISTAFLEX blend comprising DES N3200 and DES W and asingle amine, TETA. The molar equivalents ratio of amine molarequivalents to isocyanate molar equivalents was approximately 1.2:1.Formulations 613A, 613B, and 613C were prepared using a higherproportion of shell wall components compared to commercially availableDEGREE. The formulation for DEGREE employs about 8% by weight shell wallcomponents compared to the acetochlor loading. By comparison,formulations 613A, 613B, and 613C were prepared with 16% by weight shellwall components compared to the acetochlor loading.

To prepare the formulation, large batches of each of the internal phase,the external phase, the amine solution, and the stabilizer solution wereprepared containing the components and amounts shown in the followingtable:

Form. 613A Form. 613B Form. 613C Component Weight of Component (g)Internal Phase Acetochlor 507.0 NORPAR 15 26.30 MISTAFLEX H9915 81.01External Phase Glycerin 88.81 SOKALAN CP9 26.2 Ammonium Caseinate 0.52Acid 1.96 Water 320.0 TETA, 50% solution 13.56 13.56 13.57 StabilizerInvalon 71.83 Kelzan CC 0.64 Antifoam 0.01 Glycerin 48.15 Proxel GXL0.64 Caustic 0.22 Buffer 1.43

The aqueous dispersions of microcapsules were prepared substantially asdescribed above in Example 1. To prepare each formulation, the largeinternal phase, external phase, and stabilizer batches were divided intosmaller approximately equal weight batches and combined as described inExample 1. Three separate amine solutions were used to initiatepolymerization. During emulsification, the mixer speed was varied bycontrolling the blender to achieve mean particle sizes as shown in thetable:

TABLE Particle Size Parameters Formulations Mean Particle size (μm)Standard Deviation (μm) 613A 3.24 3.37 613B 7.73 5.18 613C 10.90 7.88

Example 41. Preparation of Aqueous Dispersions of MicroencapsulatedAcetochlor

Three aqueous dispersions of microencapsulated acetochlor (designatedformulation 617A, 617B, and 617C) were prepared. These formulations wereprepared using the MISTAFLEX blend comprising DES N3200 and DES W and asingle amine, TETA. The molar equivalents ratio of amine molarequivalents to isocyanate molar equivalents was approximately 1.25:1.Formulations 617A, 617B, and 617C were prepared using a similar relativeproportion of shell wall components compared to DEGREE.

To prepare the formulation, large batches of each of the internal phase,the external phase, the amine solution, and the stabilizer solution wereprepared containing the components and amounts shown in the followingtable:

Form. 617A Form. 617B Form. 617C Component Weight of Component (g)Internal Phase Acetochlor 506.78 NORPAR 15 26.33 MISTAFLEX H9915 35.48External Phase Glycerin 102.2 SOKALAN CP9 31.1 Ammonium Caseinate 0.62Acid 2.85 Water 368.3 TETA, 50% solution 6.20 6.20 6.21 StabilizerInvalon 71.83 Kelzan CC 0.64 Antifoam 0.01 Glycerin 48.15 Proxel GXL0.64 Caustic 0.22 Buffer 1.43

The aqueous dispersions of microcapsules were prepared substantially asdescribed above in Example 1. To prepare each formulation, the largeinternal phase, external phase, and stabilizer batches were divided intosmaller approximately equal weight batches and combined as described inExample 1. Three separate amine solutions were used to initiatepolymerization. During emulsification, the mixer speed was varied bycontrolling the blender to achieve mean particle sizes as shown in thetable:

TABLE Particle Size Parameters Formulations Mean Particle size (μm)Standard Deviation (μm) 617A 7.10 4.67 617B 8.93 5.75 617C 11.23 6.86

Example 42. Preparation of Aqueous Dispersions of MicroencapsulatedAcetochlor

Four aqueous dispersions of microencapsulated acetochlor (designatedformulation 621A, 621B, 621C, and 621D) were prepared. Theseformulations were prepared using the MISTAFLEX blend comprising DESN3200 and DES W and a single amine, TETA. The molar equivalents ratio ofamine molar equivalents to isocyanate molar equivalents wasapproximately 1.2:1. Formulations 621A, 621B, 621C, and 621D wereprepared using a higher proportion of shell wall components compared toDEGREE but a lower proportion compared to the formulations describedabove in Example 40. Formulations 621A, 621B, 621C, and 621D wereprepared with 12% by weight shell wall components compared to theacetochlor loading.

To prepare the formulation, large batches of each of the internal phase,the external phase, the amine solution, and the stabilizer solution wereprepared containing the components and amounts shown in the followingtable:

Form. 621A Form. 621B Form. 621C Form.621D Component Weight of Component(g) Internal Phase Acetochlor 675.72 NORPAR 15 35.10 MISTAFLEX 77.3H9915 External Phase Glycerin 127.6 SOKALAN 37.90 CP9 Ammonium 0.25Caseinate Acid 3.0 Water 461.0 TETA, 50% 9.72 9.72 9.72 9.73 solutionStabilizer Invalon 95.77 Kelzan CC 0.86 Antifoam 0.02 Glycerin 64.20Proxel GXL 0.86 Caustic 0.29 Buffer 1.91

The aqueous dispersions of microcapsules were prepared substantially asdescribed above in Example 1. To prepare each formulation, the largeinternal phase, external phase, and stabilizer batches were divided intosmaller approximately equal weight batches and combined as described inExample 1. Four separate amine solutions were used to initiatepolymerization. During emulsification, the mixer speed was varied bycontrolling the blender to achieve mean particle sizes as shown in thetable:

TABLE Particle Size Parameters Formulations Mean Particle size (μm)Standard Deviation (μm) 621A 6.70 4.42 621B 8.88 5.89 621C 2.48 2.43621D 11.53 7.02

Example 43. Study of Soybean and Cotton Crop Safety and Post-EmergenceWeed Control Efficacy Using Microencapsulated Acetochlor Formulations ofthe Invention

Formulations 613B, 613C, 617A, 617B, 621A, and 621B (prepared accordingto the methods described in Examples 40 through 42) were applied to andcotton (RR Flex—short to mid-season variety) crops under greenhouseconditions. These formulations were tested against commercialformulations DEGREE and DUAL II MAGNUM and against formulation 3997. Theformulations were applied to post-emergent cotton plants and measuredfor phytotoxicity 20 DAT. The results are shown in FIG. 70.

Formulations 617B, 621B, 613B, and 613C provided post emergent (“POE”)cotton safety that was equivalent to formulation 3997. See FIG. 70. Theleast injury among the experimental formulations was shown byformulations 613B and 613C, both of which had the highest percentage ofshell wall component. Formulations 617A and 621A showed significantlygreater injury than formulation 3997, but less than that seen withDEGREE and DUAL II MAGNUM. Both formulations have smaller capsule size,thus demonstrating once again the importance of capsule size to cropsafety. Release rates were measured in a SOTAX AT-7 dissolution testapparatus according to the method described herein. See the followingtable for the release rates of the tested formulations.

Formulation Release at 6 hours (ppm) Release at 24 hours (ppm) 613B 5265 613C 45 55 617A 77 97 617B 79 95 621A 100 123 621B 65 82 DEGREE 127182 DEGREE 118 174

Formulations 613B, 613C, 617A, 617B, 621A, and 621B were also tested forweed control efficacy and compared to the weed control efficacy ofDEGREE and DUAL II MAGNUM. The weed species tested were Barnyardgrass(Echinochloa crus-galli) and Yellow foxtail (Setaria lutescens). Theweed control efficacy data are presented in FIGS. 71 and 72.

Weed control data showed Formulations 613B and 613C to be leasteffective among the experimental formulations in the control of yellowfoxtail, although control was similar to the standards. See FIG. 71.This would suggest that the thickest shell wall with these twoformulations is slowing the release of acetochlor. This was evident to alesser degree in the control of barnyardgrass. See FIG. 72.

Example 44. Preparation of Aqueous Dispersions of MicroencapsulatedAcetochlor

Three aqueous dispersions of microencapsulated acetochlor (designatedformulations 660A, 660B, and 660C) were prepared. These formulationswere prepared using the MISTAFLEX blend comprising DES N3200 and DES Wand a single amine, TETA. The molar equivalents ratio of amine molarequivalents to isocyanate molar equivalents was approximately 1.2:1.Formulations 660A, 660B, and 660C were prepared having an acetochlorloading of about 33% by weight, which is a relatively lower proportionof acetochlor compared to DEGREE.

To prepare the formulation, large batches of each of the internal phase,the external phase, the amine solution, and the stabilizer solution wereprepared containing the components and amounts shown in the followingtable:

Form. 660A Form. 660B Form. 660C Component Weight of Component (g)Internal Phase Acetochlor 524.1 NORPAR 15 27.0 MISTAFLEX H9915 38.32External Phase Glycerin 146.40 SOKALAN CP9 43.22 Ammonium Caseinate 0.88Acid 3.15 Water 527.40 TETA, 50% solution 6.43 6.42 6.45 StabilizerInvalon 108.38 Kelzan CC 0.97 Antifoam 0.02 Glycerin 72.65 Proxel GXL0.97 Caustic 0.33 Buffer 2.16

The aqueous dispersions of microcapsules were prepared substantially asdescribed above in Example 1. To prepare each formulation, the largeinternal phase, external phase, and stabilizer batches were divided intosmaller approximately equal weight batches and combined as described inExample 1. Three amine solutions were used to initiate polymerization.During emulsification, the mixer speed was varied by controlling theblender to achieve mean particle sizes as shown in the table:

TABLE Particle Size Parameters Formulations Mean Particle size (μm)Standard Deviation (μm) 660A 12.50 8.59 660B 10.13 7.69 660C 6.83 4.77

Example 45. Preparation of Aqueous Dispersions of MicroencapsulatedAcetochlor

Three aqueous dispersions of microencapsulated acetochlor (designatedformulations 664A, 664B, and 664C) were prepared. These formulationswere prepared using the MISTAFLEX blend comprising DES N3200 and DES Wand a single amine, TETA. The molar equivalents ratio of amine molarequivalents to isocyanate molar equivalents was approximately 1.2:1.Formulations 664A, 664B, and 664C were prepared to have an acetochlorloading of about 33% by weight, which is a relatively lower proportionof acetochlor compared to DEGREE. Additionally, formulations 664A, 664B,and 664C were prepared using a different internal phase solvent, ISOPARL, compared to NORPAR as used in above Example 44.

To prepare the formulation, large batches of each of the internal phase,the external phase, the amine solution, and the stabilizer solution wereprepared containing the components and amounts shown in the followingtable:

Form. 664A Form. 664B Form. 664C Component Weight of Component (g)Internal Phase Acetochlor 524.10 ISOPAR L 54.10 MISTAFLEX H9915 40.15External Phase Glycerin 140.40 SOKALAN CP9 41.40 Ammonium Caseinate Acid3.10 Water 506.0 TETA, 50% solution 6.75 6.75 6.74 Stabilizer Invalon108.38 Kelzan CC 0.97 Antifoam 0.02 Glycerin 72.65 Proxel GXL 0.97Caustic 0.33 Buffer 2.16

The aqueous dispersions of microcapsules were prepared substantially asdescribed above in Example 1. To prepare each formulation, the largeinternal phase, external phase, and stabilizer batches were divided intosmaller approximately equal weight batches and combined as described inExample 1. Three amine solutions were used to initiate polymerization.During emulsification, the mixer speed was varied by controlling theblender to achieve mean particle sizes as shown in the table:

TABLE Particle Size Parameters Formulation Mean Particle size (μm)Standard Deviation (μm) 664A 6.84 5.24 664B 8.27 5.47 664C 9.35 5.95

Example 46. Preparation of Aqueous Dispersions of MicroencapsulatedAcetochlor

Three aqueous dispersions of microencapsulated acetochlor (designatedformulations 668A, 668B, and 668C) were prepared. These formulationswere prepared using the MISTAFLEX blend comprising DES N3200 and DES Wand a single amine, TETA. The molar equivalents ratio of amine molarequivalents to isocyanate molar equivalents was approximately 1.2:1.Formulations 668A, 668B, and 668C were prepared to have an acetochlorloading of about 33% by weight, which is a relatively lower proportionof acetochlor compared to DEGREE. Additionally, formulations 668A, 668B,and 668C were prepared using a different internal phase solvent, ExxsolD-110, compared to NORPAR as used in above Example 44.

To prepare the formulation, large batches of each of the internal phase,the external phase, the amine solution, and the stabilizer solution wereprepared containing the components and amounts shown in the followingtable:

Forms. 668A, 668B, 668C Component Weight of Component (g) Internal PhaseAcetochlor 524.10 Exxsol D-110 54.10 MISTAFLEX H9915 40.15 ExternalPhase Glycerin 140.30 SOKALAN CP9 41.40 Ammonium Caseinate 0.85 Acid3.05 Water 506.0 TETA, 50% solution 20.36 Stabilizer Invalon 108.38Kelzan CC 0.97 Antifoam 0.02 Glycerin 72.65 Proxel GXL 0.97 Caustic 0.33Buffer 2.16

The aqueous dispersions of microcapsules were prepared substantially asdescribed above in Example 1. To prepare each formulation, the largeinternal phase, external phase, amine, and stabilizer batches weredivided into smaller approximately equal weight batches and combined asdescribed in Example 1. During emulsification, the mixer speed wasvaried by controlling the blender to achieve mean particle sizes asshown in the table:

TABLE Particle Size Parameters Formulation Mean Particle size (μm)Standard Deviation (μm) 668A 6.75 4.55 668B 7.02 4.75 668C 9.75 6.16

Example 47. Preparation of Aqueous Dispersions of MicroencapsulatedAcetochlor

Three aqueous dispersions of microencapsulated acetochlor (designatedformulations 672A, 672B, and 672C) were prepared. These formulationswere prepared using the MISTAFLEX blend comprising DES N3200 and DES Wand a single amine, TETA. The molar equivalents ratio of amine molarequivalents to isocyanate molar equivalents was approximately 1.2:1.Formulations 672A, 672B, and 672C were prepared having an acetochlorloading of about 33% by weight, which is a relatively lower proportionof acetochlor compared to DEGREE. Additionally, formulations 672A, 672B,and 672C were prepared using a different internal phase solvent, ISOPARV, compared to NORPAR as used in above Example 44.

To prepare the formulation, large batches of each of the internal phase,the external phase, the amine solution, and the stabilizer solution wereprepared containing the components and amounts shown in the followingtable:

Form. 672A Form. 672B Form. 672C Component Weight of Component (g)Internal Phase Acetochlor 524.1 ISOPAR V 27.1 MISTAFLEX H9915 38.3External Phase Glycerin 146.4 SOKALAN CP9 43.2 Ammonium Caseinate 0.88Acid 3.25 Water 521.4 TETA, 50% solution 6.40 6.42 6.43 StabilizerInvalon 108.38 Kelzan CC 0.97 Antifoam 0.02 Glycerin 72.65 Proxel GXL0.97 Caustic 0.33 Buffer 2.16

The aqueous dispersions of microcapsules were prepared substantially asdescribed above in Example 1. To prepare each formulation, the largeinternal phase, external phase, and stabilizer batches were divided intosmaller approximately equal weight batches and combined as described inExample 1. Three separate amine solutions were used to initiatepolymerization. During emulsification, the mixer speed was varied bycontrolling the blender to achieve mean particle sizes as shown in thetable:

TABLE Particle Size Parameters Formulation Mean Particle size (μm)Standard Deviation (μm) 672A 8.13 5.35 672B 8.82 5.71 672C 10.82 7.59

Example 48. Study of Soybean and Cotton Crop Safety and Post-EmergenceWeed Control Efficacy Using Microencapsulated Acetochlor Formulations ofthe Invention

Formulations 664A, 664B, 664C, 668B, 668C, and 660C (prepared accordingto the methods described in Examples 44 through 47) were applied toglyphosate-tolerant (ROUNDUP READY) soybeans and glyphosate-tolerant(ROUNDUP READY) cotton (RR Flex—short to mid-season variety) crops undergreenhouse conditions. These formulations were tested against commercialformulations DEGREE and DUAL II MAGNUM and against formulation 3997. Theformulations were applied to post-emergent cotton plants and measuredfor phytotoxicity 20 DAT. The results are shown in FIG. 73 (soybeaninjury) and FIG. 74 (cotton injury).

Formulation 664B showed the best crop safety in soybeans and along withformulations 668B and 668C showed better crop safety than DEGREE at allapplication rates. See FIG. 73. Formulation 660C provided soybean safetythat was no better than that found with DEGREE. Formulations 664B, 664C,and 668C showed the best crop safety in cotton, although allexperimental formulations provided significantly better crop safety thanDEGREE. See FIG. 74. Release rates were measured in a SOTAX AT-7dissolution test apparatus according to the method described herein. Seethe following table for the release rates of the tested formulations.

Formulation Release at 6 hours (ppm) Release at 24 hours (ppm) 664A 98118 664B 75 89 664C 68 83 668B 81 94 668C 59 69 660C 118 144

Formulations 664A, 664B, 664C, 668B, 668C, and 660C were also tested forweed control efficacy and compared to the weed control efficacy ofDEGREE, DUAL II MAGNUM, and formulation 3997. The weed species testedwere Crabgrass (Digitaria sanguinalis), Barnyardgrass (Echinochloacrus-galli) and Yellow foxtail (Setaria lutescens). The weed controlefficacy data are presented in FIGS. 75, 76, and 77.

Formulations 664A and 660C consistently provided the best weed controlefficacy across species among the experimental formulations. Bothformulations were comparable to the standards, DEGREE and DUAL II MAGNUMin the control of crabgrass. See FIG. 75. All other formulations wereless effective with Formulation 664C and 668B showing the poorestperformance. A similar response was seen in the control of barnyardgrasswith formulations 664A and 660C providing control equal to thestandards. See FIG. 76. Formulation 664B was slightly less effective andformulation 664C gave the weakest control. Formulations 664A and 660Cagain showed the best control of yellow foxtail and were closely similarto DUAL1 II MAGNUM. See FIG. 77. Formulation 664B was slightly lesseffective, but comparable to DEGREE. As seen with crabgrass formulations664C and 668B gave the weakest control. Based upon crop safety and weedcontrol efficacy the best formulation tested in this group wasformulation 664B.

Example 49. Study of Soybean and Cotton Crop Safety and Post-EmergenceWeed Control Efficacy Using Microencapsulated Acetochlor Formulations ofthe Invention

Formulations 660A, 660B, 668A, 672A, 672B and 672C (prepared accordingto the methods described in Examples 44 through 47) were applied toglyphosate-tolerant (ROUNDUP READY) soybeans and glyphosate-tolerant(ROUNDUP READY) cotton (RR Flex—short to mid-season variety) crops undergreenhouse conditions. These formulations were tested against commercialformulations DEGREE and DUAL II MAGNUM and against formulation 3997. Theformulations were applied to post-emergent cotton plants and measuredfor phytotoxicity 14 DAT. The results are shown in FIG. 78 (soybeaninjury) and FIG. 79 (cotton injury).

Post-emergence applications to soybeans show all formulations to besafer than DUAL II MAGNUM at all rates and safer than DEGREE at mostrates. See FIG. 78. Overall crop injury appeared to be somewhat higherwith formulations 972A and 972B. An identical response was seen withpost-emergence applications in cotton, although overall crop injury waslower than that seen in soybeans. See FIG. 79.

Formulations 660A, 660B, 668A, 672A, 672B and 672C were also tested forweed control efficacy and compared to the weed control efficacy ofDEGREE, DUAL II MAGNUM, and formulation 3997. The weed species testedwere Crabgrass (Digitaria sanguinalis), Barnyardgrass (Echinochloacrus-galli) and Yellow foxtail (Setaria lutescens). The weed controlefficacy data are presented in FIGS. 80, 81, and 82.

Formulations 672A, 672B, and 672C consistently provided the best weedcontrol efficacy across species among the experimental formulations.These three formulations along with formulations 660B and 668A were allcomparable to DEGREE in terms of yellow foxtail control. See FIG. 80.Formulations 672A, 672B, and 672C were closest to DUAL II MAGNUM acrossall application rates, while formulations 660B and 668A were weaker atthe lowest rate. Formulation 660A provided the poorest yellow foxtailcontrol. Formulations 672A, 672B, and 672C were again closest to thestandards for crabgrass control. See FIG. 81. Formulation 660B and 668Awere less effective, with formulation 660A again showing the poorestcontrol. Barnyardgrass control showed formulations 672A, 672B, and 672Cto be comparable to DUAL II MAGNUM across application rates and betterthan Degree at the lowest rate. See FIG. 82. Formulations 660B and 668Awere similar to DEGREE and formulation 660A was again the weakestperformer.

Example 50. Preparation of Aqueous Dispersions of MicroencapsulatedAcetochlor

Three aqueous dispersions of microencapsulated acetochlor (designatedformulations 680A, 680B, and 680C) were prepared. These formulationswere prepared using the MISTAFLEX blend comprising DES N3200 and DES Wand a single amine, TETA. The molar equivalents ratio of amine molarequivalents to isocyanate molar equivalents was approximately 1.2:1.Formulations 680A, 680B, and 680C were prepared having an acetochlorloading of about 33% by weight, which is a relatively lower proportionof acetochlor compared to DEGREE.

To prepare the formulation, large batches of each of the internal phase,the external phase, the amine solution, and the stabilizer solution wereprepared containing the components and amounts shown in the followingtable:

Form. 680A Form. 680B Form. 680C Component Weight of Component (g)Internal Phase Acetochlor 524.10 NORPAR 15 27.10 MISTAFLEX H9915 38.3External Phase Glycerin 146.4 SOKALAN CP9 43.20 Ammonium Caseinate 0.88Acid 3.50 Water 527.40 TETA, 50% solution 6.42 6.43 6.42 StabilizerInvalon 108.38 Kelzan CC 0.97 Antifoam 0.02 Glycerin 72.65 Proxel GXL0.97 Caustic 0.33 Buffer 2.16

The aqueous dispersions of microcapsules were prepared substantially asdescribed above in Example 1. To prepare each formulation, the largeinternal phase, external phase, and stabilizer batches were divided intosmaller approximately equal weight batches and combined as described inExample 1. Three separate amine solutions were used to initiatepolymerization. During emulsification, the mixer speed was varied bycontrolling the blender to achieve mean particle sizes as shown in thetable:

TABLE Particle Size Parameters Formulation Mean Particle size (μm)Standard Deviation (μm) 680A 9.29 6.08 680B 7.60 5.04 680C 6.70 4.51

Example 51. Preparation of Aqueous Dispersions of MicroencapsulatedAcetochlor

Four aqueous dispersions of microencapsulated acetochlor (designatedformulations 684A, 684B, 684C, and 684D) were prepared. Theseformulations were prepared using the MISTAFLEX blend comprising DESN3200 and DES W and a single amine, TETA. The molar equivalents ratio ofamine molar equivalents to isocyanate molar equivalents wasapproximately 1.2:1. Formulations 684A, 684B, 684C, and 684D wereprepared having an acetochlor loading of about 33% by weight, which is arelatively lower proportion of acetochlor compared to DEGREE.Additionally, formulations 684A, 684B, and 684C were prepared using ahigher relative concentration of NORPAR solvent as compared to theformulations described in above Example 49. The proportion of NORPARsolvent in formulations 684A, 684B, 684C, and 684D was about 2.14% byweight, compared to 1.8% by weight in the formulations prepared inExample 50. Accordingly, the ratio of weight of acetochlor to weight ofNORPAR 15 diluent was approximately 16:1, compared to about 19:1 in theformulations 680A, 680B, and 680C of Example 50.

To prepare the formulation, large batches of each of the internal phase,the external phase, the amine solution, and the stabilizer solution wereprepared containing the components and amounts shown in the followingtable:

Form. 684A Form. 684B Form. 684C Component Weight of Component (g)Internal Phase Acetochlor 524.10 NORPAR 15 32.50 MISTAFLEX H9915 38.60External Phase Glycerin 145.2 SOKALAN CP9 42.90 Ammonium Caseinate 0.88Acid 3.30 Water 523 TETA, 50% solution 6.49 6.48 6.49 Stabilizer Invalon108.38 Kelzan CC 0.97 Antifoam 0.02 Glycerin 72.65 Proxel GXL 0.97Caustic 0.33 Buffer 2.16

The aqueous dispersions of microcapsules were prepared substantially asdescribed above in Example 1. To prepare each formulation, the largeinternal phase, external phase, and stabilizer batches were divided intosmaller approximately equal weight batches and combined as described inExample 1. Three separate amine solutions were used to initiatepolymerization. During emulsification, the mixer speed was varied bycontrolling the blender to achieve mean particle sizes as shown in thetable:

TABLE Particle Size Parameters Formulation Mean Particle size (μm)Standard Deviation (μm) 684A 8.36 5.59 684B 7.04 4.78 684C 6.33 4.35684D 10.3 —

Example 52. Study of Soybean and Cotton Crop Safety and Post-EmergenceWeed Control Efficacy Using Microencapsulated Acetochlor Formulations ofthe Invention

Formulations 680A, 680B, 680C, 684A, 684C, and 684D (prepared accordingto the methods described in Examples 50 and 51) were applied toglyphosate-tolerant (ROUNDUP READY) soybeans and glyphosate-tolerant(ROUNDUP READY) cotton (RR Flex—short to mid-season variety) crops undergreenhouse conditions. These formulations were tested against commercialformulations DEGREE and DUAL II MAGNUM and against formulation 3997. Theformulations were applied to post-emergent cotton plants and measuredfor phytotoxicity 16 DAT. The results are shown in FIG. 83 (soybeaninjury) and FIG. 84 (cotton injury).

All experimental formulations provided better soybean safety than DUALII MAGNUM at all application rates. See FIG. 83. Comparisons to DEGREEshowed the same relationship except for formulation 680C, which showedsimilar injury at the middle application rate. A surprisingly high levelof injury was observed with formulation 3997. All experimentalformulations and formulation 3997 also showed significantly less cottoninjury than DUAL II MAGNUM at all rates. See FIG. 84. Comparisons toDEGREE showed all formulations to be less injurious at the highestapplication rate. Release rates were measured in a SOTAX AT-7dissolution test apparatus according to the method described herein. Seethe following table for the release rates of the tested formulations.

Formulation Release at 6 hours (ppm) Release at 24 hours (ppm) 680A 6779 680B 82 106 680C 78 103 684A 69 92 684C 62 78 684D 80 104

Formulations 680A, 680B, 680C, 684A, 684C, and 684D were also tested forweed control efficacy and compared to the weed control efficacy ofDEGREE, DUAL II MAGNUM, and formulation 3997. The weed species testedwere White Clover (Trifolium repens), Crabgrass (Digitaria sanguinalis),Barnyardgrass (Echinochloa crus-galli) and Yellow foxtail (Setarialutescens). The weed control efficacy data are presented in FIGS. 85through 88.

Formulations 684A, 684C, and 680C all showed efficacy versus whiteclover that was equivalent to DUAL1 II MAGNUM at the two highestapplication rates. See FIG. 85. Formulation 680B was nearly equivalentto the standard at all application rates. The weakest efficacy was seenwith formulation 680A and low levels of control were also seen withDEGREE and formulation 3997. Crabgrass control showed formulations 680Cand 684C to be equivalent to DUAL II MAGNUM at the highest applicationrate. See FIG. 86. Very low levels of control were seen with DEGREE,3997, 680A, and 680B. Barnyardgrass control showed all encapsulatedformulations to be less effective than DUAL II MAGNUM at all applicationrates. See FIG. 87. The best level of control among experimentalformulations was seen with 680B, 680C, and 684C. Formulations 680B and684C provided yellow foxtail control that was equivalent to DUAL IIMAGNUM at the two highest application rates. See FIG. 88. Formulations680B, 680C, 684C, and 684D all showed efficacy that was equal to orbetter than DEGREE. Poor control was seen with 3997 and 680A. The unevenefficacy with encapsulated formulations and substantially better controlobserved with DUAL II MAGNUM suggests that this efficacy may havereceived overhead irrigation immediately after application rather thanthree days later as specified in the protocol. Delayed overheadirrigation is necessary to achieve results in the greenhouse withencapsulated formulations that more accurately reflect results in thefield. Immediate irrigation greatly magnifies differences betweenemulsified formulations such as DUAL II MAGNUM and encapsulatedformulations that are not reflective of actual field results. One mightalso expect the “680” series of formulations to be more efficacious thanthe “684” series, because higher levels of Norpar in the “684” seriesshould inhibit release of acetochlor to a greater extent.

When introducing elements of the present invention or the preferredembodiments(s) thereof, the articles “a”, “an”, “the” and “said” areintended to mean that there are one or more of the elements. The terms“comprising”, “including” and “having” are intended to be inclusive andmean that there may be additional elements other than the listedelements.

In view of the above, it will be seen that the several objects of theinvention are achieved and other advantageous results attained.

As various changes could be made in the above compositions and methodswithout departing from the scope of the invention, it is intended thatall matter contained in the above description and shown in theaccompanying figures shall be interpreted as illustrative and not in alimiting sense.

1. An herbicidal composition comprising: microcapsules dispersed in anaqueous liquid, the microcapsules comprising a shell wall comprising apolyurea and containing a water-immiscible core material comprising anacetamide herbicide, wherein the acetamide herbicide comprisesacetochlor, wherein the shell wall is formed in a polymerization mediumby a polymerization reaction between a polyisocyanate componentcomprising a polyisocyanate or mixture of polyisocyanates and apolyamine component comprising a polyamine or mixture of polyamines toform the polyurea, and wherein the microcapsules have a mean particlesize range of from about 7 μm to about 15 μm.
 2. (canceled)
 3. Theherbicidal composition of claim 1 wherein the microcapsules have a meanparticle size range of from about 8 μm to about 12 μm.
 4. The herbicidalcomposition of claim 1 wherein the ratio of amine molar equivalentscontained in the polyamine component to isocyanate molar equivalentscontained in the polyisocyanate component is from 1.1:1 to about 1.7:1.5. (canceled)
 6. The herbicidal composition of claim 1 wherein theweight to weight ratio of acetamide herbicide to the shell wall is fromabout 10:1 to about 6:1.
 7. The herbicidal composition of claim 1wherein the polyisocyanate component has a minimum average of 2.5reactive groups per polyisocyanate molecule and the polyamine componenthas an average of at least three reactive groups per polyamine molecule.8. The herbicidal composition of claim 1 wherein the polyisocyanatecomponent is a blend of a triisocyanate and a diisocyanate wherein theratio of the triisocyanate to the diisocyanate, on an isocyanateequivalent basis, is between about 90:10 and about 30:70.
 9. Theherbicidal composition of claim 1 wherein the core material furthercomprises from about 1% to about 10% by weight of a water-insolubleorganic solvent.
 10. The herbicidal composition of claim 1 wherein thecore further comprises a water-insoluble solvent at a weight ratio ofthe acetamide herbicide to the solvent of from 15 to 1, or from 20 to 1.11. The herbicidal composition of claim 9 wherein the water-insolublesolvent is a paraffinic hydrocarbon.
 12. (canceled)
 13. The herbicidalcomposition of claim 1 wherein the polyamine is of the structureNH₂(CH₂CH₂NH)_(m)CH₂CH₂NH₂ where m is from 1 to
 5. 14. The herbicidalcomposition of claim 1 where the polyisocyanate is predominately atrimer of 1,6-hexamethylene diisocyanate.
 15. The herbicidal compositionof claim 1 wherein the weight ratio of the microcapsule core to theshell wall is from 12:1 to 6:1. 16-69. (canceled)
 70. The herbicidalcomposition of claim 1 further comprising one or more co-herbicides,wherein the co-herbicide is selected from acetyl CoA carboxylaseinhibitors, organophosphorus herbicides, auxins, photosystem IIinhibitors, ALS inhibitors, protoporphyrinogen oxidase inhibitors andcarotenoid biosynthesis inhibitors, salts and esters thereof, andmixtures thereof. 71-193. (canceled)
 194. The herbicidal composition ofclaim 1 wherein the polyisocyanate component comprises an aliphaticpolyisocyanate or mixture of aliphatic polyisocyanates and wherein themicrocapsules have a mean particle size from about 9 μm to about 12 μm.195. The herbicidal composition of claim 1 wherein the compositionfurther comprises one or more of an emulsifying agent, pH buffer,thickener, biocide, preservative, antifreeze agent, antifoam agent,drift control agent, diluent, buffer, and/or anti-packing agent. 196.The herbicidal composition of claim 195 wherein the composition furthercomprises an emulsifying agent selected from the group consisting ofmaleic acid-olefin copolymers, gelatin, casein, polyvinyl alcohol,alkylated polyvinyl pyrrolidone polymers, maleic anhydride-methyl vinylether copolymers, styrene-maleic anhydride copolymers, maleicacid-butadiene and diisobutylene copolymers, sodium and calciumlignosulfonates, naphthalene formaldehyde condensate sulfonates,modified starches, and modified cellulosics.
 197. The herbicidalcomposition of claim 195 wherein the composition further comprises a pHbuffer comprising citric acid monohydrate, disodium phosphate, orcombinations thereof.
 198. The herbicidal composition of claim 195wherein the composition further comprises a thickener selected from thegroup consisting of guar- or xanthan-based gums, cellulose ethers,modified cellulosics and polymers, and microcrystalline celluloseanti-packing agents.
 199. The herbicidal composition of claim 1 whereinthe composition further comprises urea.
 200. The herbicidal compositionof claim 70 wherein the co-herbicide comprises an auxin herbicideselected from the group consisting of 2,4-D (2,4-dichlorophenoxyaceticacid), 2,4-DB (4-(2,4-dichlorophenoxy)butyric acid), dichloroprop, MCPA((4-chloro-2-methylphenoxy)acetic acid), MCPB(4-(4-chloro-2-methylphenoxy)butanoic acid), aminopyralid, clopyralid,fluroxypyr, triclopyr, diclopyr, mecoprop, dicamba, picloram andquinclorac, salts and esters thereof, and combinations thereof.